01 -
Preheat oven to 350°F (175°C) and line a cupcake pan with paper liners.
02 -
In a large bowl, combine cake mix, lemon-lime soda, oil, eggs, lemon zest, and lime zest. Mix until smooth and well incorporated.
03 -
Divide batter evenly among cupcake liners, filling each about 2/3 full.
04 -
Bake for 18-20 minutes, or until a toothpick inserted in the center comes out clean. Remove from oven and allow to cool completely.
05 -
Beat butter until light and fluffy. Gradually add powdered sugar, lemon-lime soda, vanilla, and a pinch of salt. Beat until smooth and creamy.
06 -
Frost the cooled cupcakes and garnish with lemon or lime zest or slices if desired.