Since reaching the quarterfinals in 2014 Martha Collison has written two cookbooks and a weekly column in Waitrose Weekend. She’s sharing her tips every week during The Great British Bake Off 2018


GBBO final: how to perfect caramel for a showstopper

The final week! The last 10 weeks have flown by and I have enjoyed watching this series. The bakers stepped up even when the challenges were a little far-fetched and the temperatures soared (imagine baking in that heatwave!). The final posed an eclectic set of tasks, but this masterclass is about the edible landscape showstopper.

As well as looking stunning, the bakes had to be carefully structurally planned. Caramel elements were used by all three of the bakers, as it carries wonderful flavour and can act as edible glue or used to make decorations. Although straightforward, the temperature of caramel needs to be carefully controlled to produce the results you desire. The simple process of melting it down and cooking until it turns golden brown in colour causes the sugars to break down and react with each other, creating new compounds with an array of complex aromas.

The caramelisation process starts at around 160°C, where sugar begins to melt. At 175°C, the colour will change to a pale brown and if allowed to harden, the caramel will become hard and glass-like. The caramel will continue to darken as the temperature increases, progressing from pale golden to dark amber. The further you take the caramel, the more bitter it becomes, which is desirable in some bakes to offset sweeter ingredients. Once caramel reaches 200°C, it is generally thought too dark to work with and you should start again.

You may also have heard the bakers speaking about isomalt and using it to create colourful, glass-like works of art. Isomalt is a sugar-free sweetener made from sucrose. It looks and behaves a lot like sugar, but can be heated without breaking down so it retains its sweetness and colour without caramelising. It’s perfect for using on cakes and in bakes when you want transparent colour that sets hard, and rarely becomes sticky because it doesn’t absorb water. You can buy it from cake specialist shops if you fancy having a go. 


Patisserie Week: tips for the perfect sweet shortcrust pastry

Did anyone else feel intensely stressed while watching the semi-final? The relatively simple madeleines for the signature challenge did a grand job at throwing us off the scent of the pastry onslaught to follow. It was exhausting watching the bakers tackling the marathon task of creating puff, choux and sweet shortcrust pastry to the standard of top patisseries. A truly tough challenge, especially all at the same time!

Sweet shortcrust pastry (or pâté sucrée) is the pastry the bakers used to make their delicate French dessert tarts. It is a curious concept, as the pastry shell should be strong enough to hold a filling, yet crumble and melt in the mouth when eaten.

The pastry gets its characteristically ‘short’ texture from literally shortening the gluten strands, or not allowing them to develop. Too much gluten developing in this kind of pastry will create a strong network that results in a tough and chewy pastry. By rubbing the butter into the flour, each flour particle becomes coated in fat. Gluten networks need water to form, but fat can repel this, which stops a large network forming like it would in bread. The gluten proteins can’t join together as well, so the chains are shorter, resulting in a much more crumbly texture. The addition of sugar, ground nuts or cocoa powder works wonders in breaking up the gluten structure too, so I would really recommend including them.

It is a common saying that if you have warm hands, you can’t make good pastry. This isn’t strictly true, although if you do have abnormally warm fingers I would suggest working quickly or employing the use of a food processor to stop the butter from melting. Pastry does like to be kept cold, so the chilling stages of recipes are really important. The fat needs to solidify to help it hold its shape properly when baked. Resting the dough also allows the gluten that has developed (you need a small amount to hold the dough together) to relax, which stops the pastry shrinking when you put it into the tart shell.


Danish Week: laminated pastry takes time and effort

Another new theme, and a particularly tricky one that seemed to cause problems for a lot of the bakers. There were tears and struggles as the bakers were challenged to create three Scandic bakes, ending with the piéce de résistance of Danish baking: the Danish pastry. Flaky pastries are what the Danes do best - multi-layered, soft, buttery laminated doughs, often filled with rich custards and glazed fruits. As we saw, they aren’t the easiest thing to master, but knowing the science behind the bake is helpful to get your head around it!

Making a Danish pastry is very similar to making puff pastry, only folding butter through a yeasted dough instead of just flour and water. Making proper puff pastry and Danish pastries takes time and effort, and involves bashing a lump of solid butter into a thin layer. Admittedly, it is still fairly time-consuming, so it’s something I’d usually only make at the weekend or when I’ve got a little bit of extra time on my hands.

To get great lamination in your pastries, you need to have sheets of butter evenly distributed throughout your dough. As you roll and fold, thin layers of dough and thin layers of fat begin to build up. When baked, the layers of fat melt and the water in the dough evaporates creating steam. The steam then fills the gaps left by the melted fat, this pushes the layers apart and eventually the structure sets, creating the buttery, flaky texture. Using strong flour helps keep the dough from tearing and creates more defined layers. The quality of your butter is also noteworthy, as a good French butter will contain a higher percentage of butterfat than most other kinds and will have a higher melting point, which stops it leaking out as it bakes. Finally, keep in mind that the cooler your ingredients are, the better your pastries will be. If the fat melts too early, you will lose the layers you have built up, so make sure the dough is properly chilled at all times. 


The appliance of science for perfect vegan bakes

Another Bake Off first: Vegan Week. I can only breathe a sigh of relief this wasn’t a challenge set during my time in the tent! I think we can all agree it looked tough, and really tested the bakers’ creativity with new ingredients. Vegan baking has been on the rise over the last couple of years, and the most common questions I get all relate to free-from and vegan baking. So here are a few golden rules to follow…

The most important thing to remember is that vegan baking is a science in its own right, so it’s not a case of simply substituting the ingredients within a recipe. Stick to well-tested, vegan cake recipes. Aquafaba (chickpea water), fruit puree, mashed banana and chia seeds can all perform similar binding functions to eggs, but are different structurally and therefore recipes need to be followed very carefully to achieve good results.

Work with the flavours you have. In traditional baking, eggs, butter and milk carry very gentle flavours and are great background players. Vegan baking often involves nut butters, fruit purees and lots of coconut, all which carry relatively strong flavours. Be smart and select other ingredients that work in harmony with your base ingredients. 

Go natural! A lot of colourings used to colour buttercreams and toppings won’t be vegan, so look for natural alternatives. Matcha powder creates a vibrant green, turmeric works well for yellow and beetroot powder creates a pinky/purply hue. Simply mix the powders into icings and toppings to decorate your vegan masterpiece.


Choux pastry: perfect choux needs a good gluten structure

Ah, remembering Pastry Week. I have to admit this was one of my least favourite weeks when I was in the tent. Pastry wasn’t one of my strong points, and while the ingredients are fairly simple, the precision and knowledge required to create the different types made my head spin! Since my time on the show, I’ve made it my mission to learn more about pastry and make it as foolproof as I can.

I thought the puits d'amours in the technical challenge looked so beautiful with their rings of choux perched on the top. I find it amazing that what looks like a gloopy, sticky dough can utterly transform in the oven into crisp, hollow, golden buns. The method is unlike any other pastry, with no rolling or folding involved.

Steam is the most important thing to mention about choux. When ingredients like milk and eggs are heated, the water content in each turns into steam. Choux pastry relies entirely on steam as there are no other raising agents involved. As the steam expands inside, egg proteins begin to stretch and most break, but due to the high heat the outside has already set, so the characteristic hollow middle forms.

Unlike other pastries, choux needs a strong gluten structure to hold its shape once baked. Using half strong bread flour is recommended.

The final point for baking great choux pastry is ensuring that it is baked properly. If the insides are even slightly moist, they will be weak. When removed from the oven, if any steam is left inside the buns it will condense back into water making the pastry soggy. To keep it from collapsing, I turn off the oven at the end of the baking time and leave the pastry to cool inside. The residual heat evaporates the remaining water and helps the buns stay crisp.


Lost in spice? Master the basics and your bakes will be heavenly

A Great British Bake Off first: Spice Week! I bet the tent smelt heavenly with all those gorgeous spices being baked into sticky ginger cakes and crispy biscuits. When baking with spice, it is all about accuracy, as many have overpowering strength that can dominate if used in too high a quantity. Spices perform many different functions in baking, the first being scent – when you’re sat in front of a heavily spiced bake it's the heady aroma. Every spice has a unique aroma and as it is thought that 80% of perceived flavour is determined by smell, baking with spice is guaranteed to make you hungry.

The second, and most noticable, is flavour. Spices will completely transform plain bakes into something exciting and memorable. As well as possessing powerful flavours, spices can enhance existing flavours in other foods. Instead of using salt to season, try experimenting with different spices to expel blandness from food.

Finally, spices add beautiful natural colours to bakes, as spectacularly demonstrated in many of the biscuit chandeliers. Paprika, turmeric and chilli are bold in flavour and produce colours that reflect that. Some spices, like saffron, are used largely because they impart a striking colour to breads and cakes as well as infusing flavour throughout. Brightly coloured spices make foods look vibrant and appealing. When you use a colourful spice, it’s really easy to tell how evenly the flavour is dispersed. Add a little or a lot – depending on how spiced you like it!


Making magic meringue for pavlova and roulades

A truly impressive week all-round ended rather joyfully, with no one going home after the bakers had battled it out creating meringue roulades, chocolate spheres and - to my horror - blancmange. I’m not sure this gelatine-heavy, disturbingly pink milky jelly is ready for a renaissance just yet. I’m focusing on something sweeter instead: the magic of meringue.

The basic recipe for meringue contains just two ingredients: egg white and caster sugar. It is hard to believe they come together and transform into something so dramatically different from their starting materials.

Egg white is a mixture of proteins and water molecules. When whisked, the proteins unfold and bubbly pockets of air are forced into the structure. The unfolded proteins bond, creating a ‘scaffolding’ that holds onto the air, accounting for the voluminous white foam. For a meringue, you need to whisk the egg whites into stiff peaks that don’t move when you tip the bowl upside down. If you haven’t whisked in enough air, you will have trouble when you add the sugar.

The sugar is added to the mixture once air has been locked in. Sugar granules dissolve in the water in the egg whites and allow even more air to be incorporated. Heating the sugar before adding it to the egg whites helps it to dissolve more quickly, and help prevent it from cracking.

The final stage is the baking. Heating the meringue mixture causes the water to evaporate, the air pockets to expand and the protein structure to set. To make a pavlova, a low oven temperature and long bake produces the crisp and chewy finish. Our bakers were aiming to roll their meringues into a roulade and retain a marshmallow-y texture in the middle, so a higher temperature and quicker bake is perfect.


Making chocolate collars - here's how to temper chocolate

During Cake Week the bakers experienced what must have been the start of this summer’s glorious heat wave. Lovely for enjoying cool drinks outside in the sunshine, not so ideal for making intricate chocolate collars on TV. Still, the contestants handled the heat admirably, as it can be roasting in that tent.

Tempering was mentioned a lot this week, as the contestants had to temper the chocolate to form their collars. It sounds scary, but it is simply the process of heating and cooling chocolate to specific temperatures. Bars of chocolate are already ‘in temper’, meaning they are shiny and have a snap. When you melt chocolate and allow it to cool without tempering it, the cocoa butter will solidify and it will be dull and crumbly. Tempering controls the way the cocoa butter crystals solidify. There are several ways, but ‘seeding’ is the one I like best because the only specialist equipment required is a sugar thermometer. Here’s how to do it:

1) Chop the chocolate you need into small, evenly sized pieces. Remove a third of the chocolate and set aside, melting the remainder until it reaches 45°C on a sugar thermometer.

2) Stir in the chocolate you set aside until it has melted into the mixture. Adding solid tempered chocolate into melted chocolate encourages the correct fat structure to form.

3) When there are no lumps in the chocolate, check the temperature. It should register 32°C on the thermometer and is now ready to use. Milk chocolate should be 29°C and white chocolate should be 30°C. Use the chocolate to coat truffles, make chocolate shapes or simply pipe onto the top of cakes.


Wagon wheels: how to get the jam right

Bake Off is back and the baking spirit has been reawakened across the UK. Episode one was a brilliant start to the new series, and beginning with Biscuit Week instead of the usual Cake Week was a nice change and really tested the 12 bakers’ skills.

I remember Biscuit Week being particularly challenging, as a lot of the bakes are so thin that a matter of minutes can mean the difference between under-baked and burnt.

You have to be completely switched on and make sure your oven temperature is spot-on to ensure a crisp and even bake.

Temperature was a running theme this week, with the bakers attempting components like jam and marshmallow for the technical challenge of wagon wheels that rely entirely on accurate temperatures.

A sugar thermometer is a really useful piece of kit to help get this right, as it is a part of baking that simply cannot be determined by eye. Jam needs to reach a temperature of 103-106°C in order to set. Too high and the pectin (a fibre found within fruits that gels in the presence of acid and sugar at the correct temperature) will become less effective, and too low it will not form a gel at all. When you are checking for the right temperature in your boiling jam, be sure to spot test a few areas of the mixture so you can be confident that the whole pan has reached the correct temperature.