Waitrose and Partners
Martha Collison's Favourite chocolate cake

Martha Collison's Favourite chocolate cake

Chocolate cake absolutely has to be two things: dark and moist. Martha Collison uses buttermilk in this recipe; its acidity reacts with the bicarbonate of soda to give the cake its rise. It also acts as a tenderiser, stopping tough gluten networks forming so quickly. 

4 out of 5 stars(4) Rate this recipe
  • Serves8
  • CourseCake
  • Prepare20 mins
  • Cook30 mins
  • Total time50 mins
  • Pluscooling


  • Butter, for greasing
  • 125g plain flour
  • 225g caster sugar
  • 50g cocoa powder
  • 1 tsp bicarbonate of soda
  • ¼ x ¼ tsp salt
  • 125ml buttermilk (cultured), or 110ml milk plus 1⁄2 tbsp lemon juice
  • 60g butter, melted
  • 1 eggs
  • 125ml coffee (or water)


  1. Pre heat the oven to 180°C/160°C fan/gas 4 then grease a 20cm tin and line it with baking parchment. Put the plain flour, caster sugar, cocoa powder, bicarbonate of soda and salt into a large bowl. Whisk to combine.

  2. If you don’t have buttermilk, pour the milk into a large jug and add the lemon juice. Leave to stand for five minutes until thickened.

  3. Whisk the buttermilk/acidified milk into the melted butter and egg followed by the coffee or water.

  4. Pour the wet mixture into the dry ingredients, whisking until a smooth batter has formed. It will be very runny, and if you are making more than one layer, the best way to divide it between the tins is to transfer the batter to a large jug. You can then use either the markings on the jug to measure the amount going into each tin, or put a tin on the scales and measure by weight. It is important to do this so that the layers are the same height and cook at the same rate.

  5. Bake for 25–30 minutes until risen and a skewer inserted comes out clean. Leave to cool in the tin for ten minutes before turning out onto a cooling rack.

Cook’s tip

Adding coffee to chocolate cakes really brings out the flavour in the cocoa, and you can barely taste it. If you detest coffee or are baking for children, you can use boiling water instead in any of the chocolate cake recipes

If you can t find buttermilk, mix some milk with lemon juice as a substitute. The juice will make the milk curdle, but don t worry about this.


Typical values per serving when made using specific products in recipe


1,143kJ/ 272kcals



Saturated Fat












Rating details

Rate this recipe

Select your rating

Overall rating (4/5)

4 out of 5 stars4 ratings

5 Stars


4 Stars


3 Stars


2 Stars


1 Stars