Pre-heat the oven to 180C (356F) fan-forced and line a muffin tin with cupcake cases.
Beat the butter and sugar together in an electric mixer until light and creamy.
Add the eggs and the vanilla and beat until they're well mixed in.
Take the bowl off the stand (or you can do it on the stand if you like) and using a wooden spoon, alternate stirring in the the juice with the flour and mix until just combined.
Divide the batter between the cupcake case and bake for 15-20 minutes or until a cake tester comes out clean.
Leave the cupcakes to cool on a wire rack.
Make the icing by beating the butter with an electric mixer then adding the icing sugar. Add the strawberries and beat until smooth and fluffy.
Add milk if the icing is too thick.