Preheat oven to 180°C (Gas mark 4/350°F). Line a 12 hole muffin tin with 12 muffin cases.

Place the butter into a mixing bowl and whisk together with the caster sugar until light and fluffy. Break the eggs into a bowl and lightly whisk with a fork. Add the eggs a little at a time to the butter and sugar mix, whisking in between.

Sift the flour on top, and using an electric whisk on a low speed, gently blend the ingredients together.  Add the milk and vanilla extract and blend again.  Increase the mixer speed and whisk for a few more seconds until well mixed.

Divide the cake mixture between the 12 cupcake cases and smooth over the tops with the back of a spoon. Bake for 20-25 minutes until risen, golden and springy to the touch.

Once the cakes are cooked, transfer to a wire rack to cool.

Whilst the cakes are cooling, make the buttercream icing:

Whisk the butter with an electric whisk until light and fluffy. Sift in the icing sugar, a little at a time, until completely combined. Add the vanilla extract and whisk again.

Add the milk in small splashes until the icing is at the correct consistency for piping.

Spoon the buttercream into a piping bag with a star nozzle.

Using a small sharp knife, cut a disk from the top of each cake.

Cut the disk of cake in half to make two butterfly wings.

Pipe a small swirl of buttercream into the centre of the cake.

Push the butterfly wings into the cake, rounded side first.

Top with hundreds & thousands or sprinkles of your choice (we added tiny sugar stars to ours).