If you're one of the six lucky finalists in our cake-decorating competition, you'll be asked to bake and decorate your cakes according to your submitted design and bring the finished creation to the Cake and Bake show in London on 13-15 September.

You'll need to use the easy chocolate sponge recipe below to create your cake. When it comes to decoration, let your imagination run wild!

TWO-TIER CHOCOLATE CAKE

Serves 24

Prep 1 hr Total time 3½ hrs, plus cooling
Get ahead Bake the sponges up to a day ahead; store in airtight containers. The cakes freeze well, too

Ingredients

• FOR THE TOP TIER:
• 100g soft butter
• 275g caster sugar
• ½ tsp pure vanilla extract
• 250g self-raising flour
• 50g cocoa
• 1 tsp bicarbonate of soda
• 3 large eggs, separated
• FOR THE BOTTOM TIER:
• 250g soft butter
• 550g caster sugar
• 1 tsp pure vanilla extract
• 500g self-raising flour
• 100g cocoa
• 2 tsp bicarbonate of soda
• 5 large eggs, separated

Method

1. Preheat the oven to 180°C, fan 160°C, gas 4. For the top tier, lightly butter a round 8cm-deep 18cm loose-bottomed tin and line with baking paper.
2. Using an electric hand whisk, cream the butter, 200g of the sugar and the vanilla extract in a bowl until pale and fluffy.
3. In another bowl, sift together the flour, cocoa, bicarbonate of soda and a pinch of salt. Beat this into the butter and sugar mixture a little at a time, alternately with the 3 egg yolks and 250ml of cold water.
4. In a large, clean bowl, whisk the 3 egg whites to soft peaks, then whisk in the remaining 75g of sugar, a tablespoon at a time, until stiff and shiny.
5. Fold the egg white into the chocolate mixture until combined, then spoon into the prepared tin and bake for 1 hour until a skewer comes out clean.
6. Cool the cake in the tin for 5 minutes, then turn out on to a wire rack. Peel off the baking paper and leave to cool completely.
7. To make the bottom tier, lightly butter a round 7cm-deep 25cm loose-bottomed tin and line with baking paper.
8. Cream the butter with 400g of the sugar and vanilla extract, then sift the dry ingredients together.
9. Beat the dry ingredients into the creamed butter and sugar a little at a time, alternately with the 5 egg yolks and 450ml of cold water.
10. In a large, clean bowl, whisk the 5 egg whites to soft peaks, then gradually whisk in the remaining 150g of sugar.
11. Fold the egg white into the chocolate mixture until combined, then spoon into the prepared tin. Bake for 1 hour 30 mins until a skewer comes out clean. Cool the cake for 15 minutes in the tin.
12. Place the smaller cake on top of the larger cake, in the centre, and decorate as you wish.