Transform a basic cake into an indulgent treat with easy cake fillings.
Beat together 8 tbsp (125 g) of softened butter with 3 oz (85 g) of sieved confectioners' (powdered) sugar (you may need a little more or less; adjust according to taste). Add a drop or two of vanilla extract, and beat until smooth.
If it is too stiff, it will be difficult to spread. Add other flavors to the buttercream, such as maple syrup, almond essence, Amaretto, or espresso and chocolate for a mocha filling.
Add a couple of handfuls of raspberries (or summer berries of your choice) to a pan, and sprinkle over a handful of granulated sugar. Simmer gently for about 5 minutes. Transfer to a bowl and, when cold, put in the refrigerator. Spoon over the bottom half of the cake, with a layer of fresh raspberries (or summer berries of your choice), then cover with the top layer of sponge, dust with sieved confectioners (powdered) sugar, and the white chocolate drizzle.
Whisk 4 to 5 tablespoons of heavy cream until it forms soft peaks. Spoon in 1 to 2 tbsp of ready made sweetened chestnut purée, and stir until lightly marbled. Taste, and add more purée if needed, or sweeten with sieved confectioners (powdered) sugar. Spread over the first layer of cake, and place the second layer on top. Dust with sieved confectioners sugar and cocoa powder.