Preheat your oven to 350ºF and spray a 9x13" baking pan with cooking spray.
In a large bowl, stir the lemon cake mix and pudding mix together.
1 package (15.25 ounces) lemon cake mix, 1 package (3.4 ounce) Instant lemon pudding mix
Add the water, oil, and eggs into the bowl and whisk until smooth.
3/4 cup warm water, 1/2 cup vegetable oil, 4 eggs
Pour the batter into the prepared cake pan and spread evenly.
Bake the cake for 40 minutes. The cake will be golden brown and spring back to the touch.
Remove the cake from the oven and poke holes across the entire top of the cake with a fork.
In a medium sized bowl, whisk together the lemon juice and powdered sugar. Pour the glaze over the top of the hot cake, going slowly so it has time to absorb into the cake as you pour.
1/2 cup lemon juice, 2 cups powdered sugar
Let the cake cool then slice and serve.