01 - Preheat oven to 350°F. Grease a 9x13-inch baking pan thoroughly.
02 - Combine cake mix, water, oil, and eggs in a large bowl. Beat on medium speed for 2 minutes until completely smooth.
03 - Pour batter into prepared pan. Bake for 28-32 minutes until a toothpick inserted in the center comes out clean.
04 - Remove from oven and let cool for 15 minutes. Using a wooden spoon handle, poke holes across the entire cake surface, spacing approximately 1 inch apart.
05 - Dissolve lime gelatin in boiling water, stirring until completely dissolved. Stir in cold water.
06 - Slowly pour the gelatin mixture evenly over the warm cake, ensuring it seeps into all the poked holes.
07 - Refrigerate for at least 2 hours to allow the gelatin to fully set within the cake.
08 - Spread whipped topping evenly over the entire surface of the chilled cake.
09 - Sprinkle with lime zest and add green sprinkles or lime slices if desired. Cut into squares and serve chilled.