Lemon Curd Butterfly Cakes

Pre-heat the oven to gas mark 5/375F/190u0b0C.
You will need a 12-cup muffin tin lined with cupcake baking cases.
To make the cakes, sift the flour and salt in a bowl.
Then add in the rest of the ingredients in bowl and beat until absolutely smooth - 1-2 minutes.
Then fill prepared muffin tin with the mixture and tap the tin two or three times to settle the cake mix.
Bake on the centre shelf of the oven for 15-20 minutes or until the cakes are well risen and golden.
Remove the cakes from the tin and transfer onto a wire rack and leave to cool.
To make the lemon curd, place the grated lemon rind and sugar in a bowl.
In another bowl, whisk the lemon juice together with the eggs, then pour the mixture over the sugar.
Add the butter cut into small pieces, and place the bowl over a pan of barely simmering water.
Stir frequently till thickened - for about 20 minutes.
Cool the curd before using it for the filling (these can be stored in a clean dry jar with a screw-top lid, refrigerated and used within a week).
To assemble the cake, take a small sharp knife and cut the top off each at an angle in a circle about 1/2 inch (1 cm) from the edge of the cake so that you remove a cone-shaped round, leaving a cavity in the centre.
Cut the round in half, top to bottom, and set aside.
Now fill the cavity of each cake with the lemon curd then sit the two cone-shaped pieces of cake on top like butterfly wings.
Dust with icing sugar to serve.