Preheat oven to 350°F. Spray a 9x13 baking dish with nonstick cooking spray and set aside.

In a bowl, add the lemon cake mix, melted butter, and 1 egg. Mix well. The dough will be thick and stiff, more like cookie dough than cake batter, and that is normal. Pour into the prepared pan and press firmly and evenly into the bottom with your fingers, making sure the layer is even so it bakes evenly.

In a separate bowl, add the softened cream cheese, remaining 2 eggs, powdered sugar, and lemon juice. Beat until completely smooth with no lumps. Letting the cream cheese sit out ahead of time helps it blend smooth here instead of leaving little lumps. Pour over the crust and spread evenly to the edges.

Bake for 25 to 30 minutes, until the edges just start to turn brown. The center will still look soft and a little jiggly, which is normal.

Remove from the oven and cool completely before slicing, or the topping will not set up properly. For the cleanest cuts, chill the pan first and wipe your knife clean between cuts.