Chocolate frosting

Beat softened butter until creamy, then gradually beat in sifted icing sugar and cocoa powder. Add a little milk, a spoonful at a time, until it spreads easily; a pinch of salt helps balance the sweetness.

For thick frosting, beat in milk a teaspoon at a time. If it is too runny, beat in sifted icing sugar gradually; chilling it briefly can also firm up butter-based frosting.

Wait until the cake is completely cool, or the butter in the frosting can melt and slide off. Spread a thin first layer to catch crumbs, chill it until firm, then add the final layer.

Keep butter-based chocolate frosting in an airtight container in the fridge for up to five days. Let it soften at room temperature, then beat it briefly before spreading.

Yes. Freeze it in an airtight container for up to three months, then thaw it in the fridge overnight; bring it to room temperature and beat until smooth before using.

It is a classic finish for chocolate, vanilla and red velvet cakes, and works well between layers of a sponge cake. You can also spread it on cupcakes or sandwich it between biscuits.

Chocolate frosting is usually beaten with butter and icing sugar, so it is fluffy and easy to pipe. Ganache is made by pouring hot cream over chopped chocolate; it sets denser and glossier, and can be poured while warm as a cake coating.