Preheat oven to 350°F. Line a muffin tin with cupcake liners.

In a medium bowl, whisk together flour, baking powder, baking soda, and salt.

In a large bowl, beat butter and sugar until light and fluffy, about 2 minutes.

Add eggs one at a time, mixing well after each. Stir in vanilla extract.

Alternate adding dry ingredients and the buttermilk/milk mixture, mixing just until combined.

Stir in green food coloring until evenly tinted.

Divide batter evenly into liners, filling each about ¾ full.

Bake 18–20 minutes, or until a toothpick inserted in the center comes out clean.

Cool completely before frosting.

For frosting, beat butter until creamy. Gradually add powdered sugar. Mix in vanilla, salt, and cream until fluffy.

Pipe or spread frosting onto cooled cupcakes and decorate.