Chocolate swirl cupcakes

Set the oven to gas mark 5 or 190°C.

To make the cupcakes: place all the ingredients in a bowl and beat until smooth.

Divide the mixture between the paper cases, and bake in the centre of the oven for 15-18 mins, or until the cakes have risen and are just firm to the touch in the centre.

Remove cakes from the oven, transfer them to a wire rack to cool.

To make the buttercream: Tip the egg whites into a bowl and add the sugar and salt.

Place the bowl over a pan of simmering water and stir until the sugar dissolves completely, and when you put your fingers in the mixture you can't feel any grains of sugar Remove the bowl from the heat and whisk the mixture, preferably using a table-top mixer, until it becomes a thick meringue and whisk in the vanilla extract.

Cut the butter into chunks and whisk it in - the mixture may collapse and go runny, but keep whisking it at full speed and it will combine together to give a fluffy buttercream.

Gradually whisk in the melted chocolate.

Fill the piping bag with the chocolate buttercream and pipe a swirl onto the top of each cupcake. Press a chocolate shape/decoration into the top of each.