Preheat oven to 175°C. Prepare a muffin tin by oiling or lining up with paper moulds. Melt butter on medium heat, let it cool.

Whisk together flour, baking powder, baking soda, salt and sugar. In another bowl mix egg, vanilla and milk.

Combine dry ingredients with milk-egg mix and the warm butter. Mix until a shiny dough comes out. Pour into prepared moulds and bake for about 25 minutes or a toothpick insert comes out clean. Let them cool on a wire rack

For the frosting. Sift the confectioners sugar and combine with espresso and then with mascarpone and cream cheese. Decorate cupcakes as you like.