Ingredients

Step by step

1. Put the chocolate and butter in a heatproof bowl and set over a pan of simmering water (make sure the base of the bowl doesn’t touch the water). Allow to melt, stirring occasionally, then set aside to cool to room temperature.

2. Meanwhile, preheat the oven to 180°C, fan 160°C, gas 4. Butter 3 x 18cm round cake tins and line the bases with baking paper. Sift the flour, cocoa powder, baking powder and bicarb into a large bowl, then add the brown sugar and salt. Stir to combine and set aside.

3. Once the chocolate mixture has cooled, beat the eggs, oil and milk together in a measuring jug. Make a well in the centre of the dry ingredients, then pour in the egg and chocolate mixtures. Use a balloon whisk to whisk to a thick, smooth batter. Pour in 160ml of hot (not boiling) water and continue to whisk until combined.

4. Divide the batter evenly among the prepared tins, then bake for 25-30 minutes, or until a skewer inserted comes out clean. Cool in the tins for 15 minutes, then turn out onto a wire rack, peel off the baking paper and leave to cool completely. Increase the oven to 190°C, fan 170°C, gas 5.

5. For the sesame brittle, spread the sesame seeds out on a baking tray, then toast for 10-12 minutes, until golden. Tear off 2 sheets of baking paper and set aside. Put the sugar, glucose, butter and a pinch of salt in a small saucepan. Stir continuously over a medium-high heat, until starting to come to the boil. Remove from the heat and stir in the sesame seeds. Pour the sesame caramel onto one of the baking paper sheets (on a heatproof surface), cover with the other sheet and use a rolling pin to spread the caramel to 2mm thickness. Slide onto a large baking sheet, remove the top layer of paper and bake for 15-17 minutes, until golden. Set aside to cool completely.

6. For the buttercream, use an electric mixer to beat the butter, tahini, vanilla and salt for 1-2 minutes until smooth. Beat in the sifted icing sugar in two batches, until combined, then continue to beat for 2-3 minutes until smooth and lighter in colour.

7. Use a long serrated knife to trim the domes off the tops of the sponges, if necessary. Place one of the sponges on a cake stand or serving plate and spread with some of the buttercream. Top with another sponge layer, repeat with more buttercream and then top with the final sponge. Cover the whole cake with the rest of the buttercream, smoothing it over with a palette knife. You can chill the cake at this point a few hours ahead. Crumble about half of the sesame brittle into small pieces and use to decorate the top of the cake. Enjoy the remaining brittle alongside or as a sweet snack over the following week.