Ingredients:
1 ¾ cups cake flour
½ teaspoon baking powder
½ teaspoon baking soda
½ teaspoon salt
1 stick (1/2 cup) cool unsalted butter, cut into 8 pieces
1 ¼ cups granulated sugar
2 large eggs (room temperature)
2 ½ tablespoons key lime juice
1 tablespoon key lime zest
1 drop green food coloring paste
¾ cup buttermilk (room temperature)
Icing:
1 stick cool unsalted butter, cut into 8 pieces
8 ounces cream cheese (room temperature), cut into 8 pieces
2 ¼ cups powdered sugar, sifted
1 tablespoon key lime zest
Preheat oven to 350*F. Line a muffin tin with 12 paper liners.
Sift the cake flour, baking powder, baking soda, and salt three times, set aside.
Using a mixer fitted with the paddle attachment, beat the butter on low until it’s softened a bit. Add the sugar and increase the speed to medium. Beat until fluffy, about four minutes. Add one egg at a time, beating well after each addition. Add the lime juice, zest, and food coloring and beat until mixed. (The mixture will look curdled.)
Add the flour in three additions, alternating with the buttermilk, beginning and ending with the flour, scraping down the bowl as necessary. Mix on low until just combined. Fill each cupcake liner 2/3 full.
Bake 20-25 minutes. Cool completely and frost with cream cheese icing.
Makes 12-14 cupcakes.
Icing:
Using a mixer fitted with the paddle attachment, beat the butter on low until it’s softened a bit. Increase speed to medium and add the cream cheese one piece at a time. Reduce speed to low and slowly add powdered sugar until combined. Beat in zest.
Source: http://mymadisonbistro.com/archives/key-lime-cupcakes
