Step 1

Preheat oven to 350 degrees. Spray a 9-inch round cake pan with nonstick spray.

Step 2

In a large bowl, stir cake mix with undrained pineapple until uniform. (Batter will be thick, but DON'T add anything else!)

Step 3

Spread batter into the cake pan. Bake until a toothpick inserted into the center comes out mostly clean, 18 - 20 minutes.

Step 4

Let cool completely, about 30 minutes in the pan and 30 minutes out of the pan on a cooling rack.