01 - Preheat oven to 350°F and grease a 9x13-inch baking pan.
02 - Combine cake mix, water, vegetable oil, and eggs in a large bowl. Beat on medium speed for 2 minutes until smooth. Pour batter into prepared pan and level the surface.
03 - Bake for 28 to 32 minutes until a toothpick inserted in the center emerges clean. Remove from oven and allow to cool for 10 minutes.
04 - Using the handle of a wooden spoon, poke holes evenly across the warm cake, spacing approximately 1 inch apart.
05 - Dissolve lime gelatin in 1 cup boiling water, then stir in 1/2 cup cold water.
06 - Pour the gelatin mixture evenly over the warm cake, allowing it to fill the holes completely.
07 - Refrigerate for at least 1 hour until the gelatin is fully set.
08 - Whisk cold milk and vanilla pudding mix for 2 minutes until slightly thickened. Gently fold in whipped topping until thoroughly combined.
09 - Spread the pudding mixture evenly over the chilled cake. Sprinkle with lime zest and green sprinkles as desired.
10 - Refrigerate for at least 30 minutes before serving. Cut into squares to serve.