In a large bowl cream the butter and sugar together until combined
Add the milk, lemon juice and eggs into the mix then whisk until incorporated
Add the flour, lemon zest and baking powder into the mixture then whisk until all the ingredients are combined
Line a cupcake tray with cupcake cases and divide the batter evenly between the cases
Bake in the centre of a preheated oven at 160°C/325°F/gas mark 3 for 25-30 minutes
Transfer to a wire rack to allow to cool completely whilst the frosting is prepared
In a bowl whip the butter until pale and fluffy – the butter will have doubled in volume
Add the icing sugar and lemon juice and whisk until incorporated
Add the double cream and whisk until smooth and creamy
Your lemon cupcakes with lemon buttercream frosting are ready!