Mix the lemon cake mix according to package directions, EXCEPT substitute half of the water with lime juice, (i.e. if you need 1 1/2 cups of water, use 3/4 cup water and 3/4 cup lime juice) and add the box of lime jello.
Prepare your pan(s) with cooking spray, or by using our wax paper technique found above.
Cook according to package directions.
While cake is cooking, prepare the frosting by placing the powder sugar, premade frosting, and lime juice in a bowl. Beat until smooth.
Once the cake has cooled, remove from pans and take off wax paper if used.
Frost your cake, and enjoy!