Chocolate marshmallow brownie cake

1. Preheat the oven to 180C/gas 4.

2. Sieve the flour, half of the cocoa powder, the baking powder and salt together in a large bowl.

3. In another bowl, whisk together the eggs, caster sugar, butter, milk, and vanilla essence. Add to the flour and stir the batter until just combined.

4. Stir in the walnuts and marshmallows and spread the batter evenly into a 20cm square cake tin.

5. In a separate bowl, beat the remaining cocoa powder, demerara sugar, melted chocolate and boiling water together until smooth. Pour the mixture over the batter in the tin and bake for 35 to 40 minutes.

6. Serve the cake hot with crème fraîche.

Recipe: Paul Bloxham