Definitely @rockjon!

Ingredients

Cupcakes:
5 egg whites
1 cup milk
1/2 cup oil
1/2 cup (1 stick) butter
2 cups sugar
1 tablespoon baking powder
1 teaspoon salt
2 teaspoons vanilla extract
3 cups flour
3 tablespoons Pisco Sour *see note
2 tablespoons lemon juice
Frosting:
6 1/2 cups powdered sugar
1 cup (2 sticks) butter, room temp
2 teaspoons vanilla extract
5 teaspoons Pisco Sour *see note
1 tablspoon lemon juice
1/4 teaspoon salt

Instructions
For Cupcakes:

1. Preheat oven to 350 degrees F (180 C). Pour egg whites into bowl of stand mixer and beat until they form stiff peaks. In separate bowl, cream butter and sugar. Add all other ingredients and mix until smooth. Fold in egg whites. Line two 12-cavity cupcake pans with paper liners and spoon batter into them to fill about 3/4 full. Bake for 25 - 35 minutes until toothpick inserted in center comes out clean. Cool completely before frosting.
   For Frosting:
2. Beat butter in a large mixing bowl until creamed. Add vanilla, salt, and powdered sugar one cup at a time. Add lemon juice and Pisco Sour and beat until light and fluffy. Use a pastry bag and tip to pipe onto cupcakes when cooled.
   Notes

*If you can't find Pisco Sour you can try replacing the 3 tablespoons in the cupcakes with 1 1/2 tablespoons tequila and 1 1/2 more lemon juice. For the frosting replace 2 1/2 teaspoons with tequila and 2 1/2 with lemon juice.