Blackberry, Lemon & White Chocolate Cake

Recipe adapted from Serious Eats

Blackberry, Lemon & White Chocolate Cake

Ingredients:For the Cake
350g (1 ¾ cups) caster sugar
2tbsp lemon zest, grated
60ml (¼ cup) lemon juice
255g (2 ¼ cups) cake flour
2tsp baking powder
1tsp bicarbonate of soda
180ml (¾ cup) milk
1tsp vanilla extract
4 eggs, separated
1tsp salt
225g (1 cup) unsalted butter
For the white chocolate frosting300g (1 ½) cups caster sugar
1tbsp lemon zest, grated
180ml (¾ cup) lemon juice
40g (¼ cup) plain flour
28g (¼ cup) cornflour
½ tsp salt
360ml (1 ½ cups) milk
280g (10 ounces) white chocolate, chopped
1tbsp vanilla extract
225g (1 cup) unsalted butterFor the assemblyblackberry jam
280g white chocolate, chopped
fresh blackberries1-2tbsp icing sugar

Method:
1. Preheat the oven to 180C/350F/mark 4 and grease and line two 9-inch cake pans.

2. For the cake, combine 300g of the sugar and lemon zest in a food processor until no zest strands remain.

3. Sift together the flour, baking powder and bicarbonate of soda and set aside.

4. In another bowl, combine the milk, lemon juice and vanilla.

5. Whisk the egg whites and salt until soft peaks form. Gradually add the remaining 50g sugar and continue whisking until stiff peaks form.

6. In a separate bowl, cream the butter and lemon sugar until light and fluffy. Add the egg yolks, one at a time. Add the flour mixture in thirds, alternating with the milk mixture. Stir one third of the egg whites into the batter until fully incorporated. Fold in the remaining egg whites.

7. Divide the batter between the prepared pans and bake for 20-25 minutes, until a skewer inserted into the centre of the cakes comes out clean. Transfer to wire racks to cool for 10 minutes before removing from the pans and leaving to cool completely.

8. For the frosting, combine the sugar and lemon zest in a food processor until no zest remains.

9. Transfer the lemon sugar to a medium saucepan, add the lemon juice and bring to a boil over a medium-high heat. Cook until reduced to 80ml (1/3 cup), 10 to 15 minutes.

10. Combine the flour, cornflour and salt. Add the milk and whisk until smooth and add to the saucepan. Cook for about 5-7 minutes over a medium heat, whisking constantly until the mixture boils and thickens. Stir in the lemon mixture, white chocolate and vanilla. Transfer to a bowl to cool to room temperature.

11. Beat the frosting mixture in a free-standing mixer with the whisk attachment. Add the butter, in tablespoon-sized pieces, until completely incorporated. Increase the speed of the mixer and beat until light and fluffy.

12. To assemble, slice each cake in half and sandwich the first two layers together with blackberry jam. Spread some of the frosting on top and add the other cake layer. Spread some blackberry jam on top and then add the final cake layer. Frost the top and sides with the frosting.

13. Melt the chocolate and spread in a thin layer over a sheet of foil. Leave to cool to room temperature, refrigerate until hard and break into shards. Press the shards into the sides of the cake, then top with the blackberries and dust with icing sugar.