• Preheat oven to 350°F.
• Line a standard sized cupcake pan with cupcake liners. I find that foil liners work the best. This recipe makes 18 cupcakes, so if you only have one pan with 12 wells, you will need to save batter for a second batch.
• Put the cake mix, thawed margarita mix, zest and juice of 1 medium lime, the egg whites, and the vegetable oil in a large mixing bowl or stand mixer bowl. Mix on low speed for 30 seconds, and then increase speed to beat on medium speed for 2 minutes.
  1 package coconut cake mix, 1 cup frozen margarita mix, 1 medium lime, 3 large egg whites, 3 tbsp vegetable oil
• Fill each cupcake liner with about ⅓ cup of batter. The liner should be about ⅔ of the way full.
• Bake at 350°F for 15 minutes, or until a tester inserted in the center of the cupcakes comes out clean.
• Let sit in pan for 10 minutes before transferring cupcakes to a cooling rack to cool completely before frosting.

Lime Buttercream Frosting

• In a large mixing bowl or stand mixer bowl, beat the butter until light and fluffy. Scrape down the sides of the bowl.
  1 cup butter
• Add the confectioners sugar 1 cup at a time, beating after each addition until the sugar is incorporated.
  6 cups confectioners sugar
• Add the vanilla extract and lime juice, mixing until incorporated.
  2 tbsp pure vanilla extract, 2 small limes
• Add the lime zest, and mix just a few seconds to incorporate.
  2 small limes
• If the frosting consistency is too thin, add confectioners sugar 1 tbsp at a time. If the frosting is too stiff, add a few more drops of lime juice.
• Put the frosting into a piping bag fitted with a large tip, such as a Wilton 1M star tip. Pipe the frosting onto the cupcakes.