Preheat the oven to 180C / 400F. Line your muffin tin with 12 cupcake cases.
Either in a stand mixer or a large bowl with a wooden spoon, cream together the butter, sugar, and vanilla until light, pale and creamy.
In a separate bowl, beat the eggs and milk, then pour one-third of this mixture into the butter and sugar and stir to combine. Repeat this with the remaining two-thirds.
Gradually add one-third of the flour and fold to combine, repeat this with the remaining two-thirds until all ingredients are mixed.
Divide your mixture into the muffin cases and bake in the oven for 20 minutes. When cooked, they should be golden and springy to touch. Leave the cakes to cool in the tins for about 10 minutes and then transfer to a wire rack to cool completely. In the meantime, make the buttercream by beating together the butter and icing sugar until the mixture is light and airy.
Pour in the vanilla and milk, if the mixture is too stiff, add a drop more milk.
Using a piping bag or simply use teaspoons decorate each cupcake with icing and enjoy!
