Chocolate marshmallow cupcakes

Preheat oven to 180°C/350°F/Gas Mark 4. Line a 12-hole muffin tin with cupcake cases.

Stir the hot water with the cocoa until smooth and leave to cool.

Sift the flour, baking powder, baking soda and salt together and set aside.

Cream the butter and sugar until light and fluffy, add the vanilla extract. Add the eggs one at a time, beating well after each addition. Add the flour in one go and then the cooled cocoa powder.

Spoon the mixture into the cupcake cases and bake for 18 minutes or until a cocktail stick inserted into the centre comes out clean. Place on wire racks to cool completely.

For the frosting: In a small saucepan, combine the sugar with the water and bring to a boil over moderately high heat, stirring constantly until the sugar has dissolved (around 2 to 3 minutes.)

Add the cream of tartar and salt to the egg whites and whisk until soft peaks form.

With the mixer at medium speed, carefully pour the hot sugar syrup into the egg whites. Continue beating the frosting until cool and billowy (around 5 minutes.)

Immediately pipe onto the cupcakes using a round tip nozzle.