Instructions

1. Heat oven to 350 degrees. Lightly grease and flour a 9-by-13-inch metal or glass cake pan. Set aside.
2. Prepare white cake mix as directed on box using the vegetable oil and eggs, EXCEPT substitute equal amount of prepared limeade for the water and add 1 tablespoon grated lime peel. Pour batter into prepared pan.
3. Bake cake as directed on box.
4. Measure ¾ cup prepared limeade into a liquid measuring cup and stir in 2 to 3 drops green food color. Remove cake from oven and allow to cool for 15 minutes, then pierce the top of the warm cake every inch with the end of a chopstick or ¼-inch diameter wooden spoon handle, wiping off as necessary to minimize sticking. 
5. Evenly spoon limeade mixture slowly over top of cake allowing liquid to fill holes. Cool completely, about 1 to 2 hours.
6. In a small bowl, whip 2 teaspoons lime zest into the fluffy white frosting, then spread evenly over cake. Cover loosely and store in refrigerator. Garnish with fresh lime twists.