Chocolate cake is a beautiful thing on its own, but Martha Collison, youngest-ever contestant on the Great British Bake Off, has a recipe that is even more delicious thanks to the addition of a thick layer of sharp passionfruit curd to undercut the heavy richness and balance the sweetness. One slice is no longer enough! This delicious layer cake is adapted from a recipe in Martha’s new book ‘Twist’, launching in July 2016.
For the Chocolate Cake
- 250g plain flour
- 450g Fairtrade caster sugar
- 100g Divine Chocolate cocoa powder
- 2 tsp bicarbonate of soda
- ½ tsp salt
- 250ml buttermilk
- 120g butter, melted
- 2 eggs
- 250ml Fairtrade coffee or water
For the Filling
- 150ml double cream
- 1 tbsp Fairtrade icing sugar
- 10 tbsp passionfruit curd
Passionfruit Curd (makes 2 small jars)
- 10 passionfruit, halved and flesh scooped out of the skins
- 100g unsalted butter
- 150g Fairtrade caster sugar
- 2 eggs, plus 2 yolks
For the Icing
- 50g butter
- 100g Divine 70% Dark Chocolate Baking Bar, chopped
- 75g Fairtrade icing sugar
- 1 tsp milk
- Chocolate shavings, to decorate
You will need
- Two round 20cm cake tins, or if you only have one tin you can slice the cake horizontally to create two layers
To Make the Cake:
- Preheat the oven to 180°C/160°C fan/gas 4. Grease and line your tin(s) with baking parchment. Put the plain flour, caster sugar, cocoa powder, bicarbonate of soda and salt into a large bowl. Whisk to combine
- Whisk the buttermilk into the melted butter and egg followed by the coffee or water
- 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 it by weight. It is important to do this so that the layers are the same height and cook at the same rate
- Bake for around 30-35 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.
To Make the Passionfruit Curd:
- Sterilise the jars and lids you are using. To do this, wash your jars and the lids in hot soapy water, but do not dry them – place upside down on a roasting tray while still wet and put in a preheated oven at 160-180ºC for about 15 minutes. After this, put the jars to one side.
- Briefly whizz the passionfruit pulp in a food processor to loosen the seeds from the juice. Strain the liquid through a sieve into a jug – this will be your fruit juice. If you want a curd with seeds in it then reserve a few tablespoons of the leftover pulp to stir into the curd before you pour it into the jars
- In a medium saucepan, combine the juice with all the other ingredients. Heat on low. Whisking all the time, until the butter has completely melted.
- Turn the heat up to medium and continue to whisk constantly. After 5-6 minutes, the mixture will thicken enough to coat the back of a spoon. Remove from the heat, pour into the sterilised jars and screw on the lids. The curd will keep in the fridge for up to two weeks.
To assemble the cake:
- Whip the cream and icing sugar together in a small bowl until it forms soft peaks and holds its shape when mixed. Be careful to stop when it reaches soft peaks or you might over whip the cream which will ruin the finished cake
- Spread the whipped cream all over the top of one of the sponges, then cover with spoonfuls of passionfruit curd. Carefully sandwich the second sponge on top
- To make the icing, melt the butter and chocolate together in a microwave or heat proof bowl over a pan of simmering water. Remove from the heat and mix in the icing sugar and milk, then use a palette knife to spread it over the top of the cake.
- Decorate with chocolate curls before serving. Keep any leftover cake in the fridge where it will keep well for 2-3 days.
To make chocolate curls
- Use a 100g bar of Divine Milk or 70% Dark Chocolate, or half a 200g Baking Bar in your desired flavour
- Remove from the wrapper and place on a piece of kitchen paper, then microwave 1 minute on medium, turning the chocolate every 10 seconds. The bar should feel warm, but not melted
- Place on a board flat side up and with a sharp, long knife, place the blade at an angle on to the chocolate and carefully pull the blade towards you to form a thin curl of chocolate. Turn the bar after each curl
- If the curls are brittle, warm the chocolate as before for a few seconds. Place on a plate and chill the curls before using to decorate your cake