Garnish with lime zest and toasted coconut flakesif desired
Preheat oven to 325 degrees F.
In the bowl of an electric mixer fitted with the paddle attachment, cream the butter and sugar on high speed until light and fluffy, about 5 minutes. Turn the mixer to low speed and add the eggs, 1 at a time, scraping down the bowl once or twice. Add the vanilla extract, lime zest and juice and mix well. In a separate bowl, sift together the flour, baking powder, baking soda, and salt. In 3 parts total, alternately add the dry ingredients and the buttermilk to the batter, beginning and ending with the dry. Mix until just combined. Using a spatula, fold the coconut into the cupcake batter.
Line a muffin pan with paper liners and fill each liner almost to the top with batter. Using 1/4 cup ice cream scoop or measuring cup is a great way to ensure cupcakes are all the same size. Bake for 20-25 minutes or until the tops just begin to color and a toothpick comes out clean. Remove cupcakes from oven and allow to cool in the pan for 10 minutes and then transfer cupcakes to a baking rack to cool completely.
While the cupcakes are cooling you can make the frosting. In the bowl of an electric mixer fitted with the paddle attachment, cream butter, cream cheese, juice and zest until light and fluffy. Add 4 cups confectioners' sugar, one cup at a time; continue beating until light and fluffy. If icing is too runny, add additional confectioners' sugar 1 tablespoon at a time.
Frost the cupcakes and garnish with a bit of grated lime zest and toasted coconut flakes.
Key limes are fantastic if you can find them but if you can’t, just use regular Persian limes.