Martha Collison's gingerbread s'more biscuits

1. Heat the butter, dark brown sugar and golden syrup in a saucepan until the butter has melted and the mixture is bubbling.

2. Combine the flour, bicarbonate of soda and spices in a large mixing bowl and make a well in the centre. Pour the wet ingredients into the well.

3. Mix the ingredients together using a wooden spoon until a thick dough comes together. As soon as it becomes smooth stop stirring or your biscuits will become tough. Allow the mixture to sit at room temperature for 5 minutes to cool.

4. Preheat the oven to 180°C, gas mark 4 and line 2 baking sheets with baking parchment. Roll out the biscuit dough to the thickness of a £1 coin and then slice into 50 even-sized rectangles. Arrange on the baking trays and bake for 14-15 minutes or until golden brown round the edges, swapping the trays over for the last few minutes. Allow to cool completely.

5. To make the filling, place the sugar, golden syrup and 2 tbsp of water into a saucepan and cook on a medium-high heat without stirring until the mixture reaches the soft-ball stage (118°C on a sugar thermometer). If you don’t have a thermometer, the mixture is ready when the bubbles start to stick together and it drips off a spoon in a steady stream. Remove from the heat.

6. Place the egg whites into the bowl of a stand mixer fitted with the whisk attachment and whisk until soft peaks form. With the mixer on low speed, carefully pour the hot sugar into the bowl. When all the sugar has been added, increase the mixer to high speed and whip until the sides of the bowl feel only slightly warm and the mixture is thick and glossy. Add the vanilla extract at the end and spoon the mixture into a piping bag.

7. Cover the top of half the gingerbread biscuits with a generous amount of dark chocolate. Pipe the marshmallow mixture onto the bottom of the remaining biscuits, then sandwich the 2 together to form a s’more.