Preheat oven to 350 degrees F (177 degrees C) and butter or line 12 muffin cups with paper liners.

For the Cupcakes: Cream the butter and sugar until light and fluffy. Add the eggs, one at a time, beating well after each addition. Beat in the vanilla extract and lemon zest. 

In a separate bowl whisk together the flour, baking powder, and salt. 

With the mixer on low speed, alternately add the flour mixture and milk, in three additions, beginning and ending with the flour. Scrape down the sides of the bowl.

Evenly fill the muffin cups with the batter and bake for about 18-20 minutes or until nicely browned and a toothpick inserted into a cupcake comes out clean. Remove from oven and place on a wire rack to cool. Once the cupcakes have completely cooled, frost with icing. If you want flat topped cupcakes then slice off the dome of each cupcake, with a sharp knife, before frosting. 

For the Frosting: In an electric mixer, or with a hand mixer, cream the butter until smooth and well blended. Add the vanilla extract. With the mixer on low speed, gradually beat in the sugar. Scrape down the sides of the bowl. Add the milk and beat on high speed until frosting is light and fluffy (about 3-4 minutes). Add a little more milk or sugar, if needed. Tint the frosting with desired food color (I use the paste food coloring that is available at cake decorating stores and party stores).

Makes about 12 cupcakes