This is so easy and delicious!
You need a 9X13 pan. Set your oven on 350*. Take a stick of BUTTER and melt it in the pan. Now put brown sugar over the butter. "Some." I really don't measure it, just eyeball it. Enough to soak up most of the butter. Now, open a can of pineapple and drain it into a measing cup.
Your going to use a cake mix. Yellow cake. I like the "butter recipe" one. See how much water the recipe calls for, and use the juice from the can in place of the water. If there's not enough juice, add enough water to make up the amount.
If your using chunk pieapple, just distribute it evenly. If using rings, you may need 2 cans to make it look right. I like to add a marachino cherry to the centers of the rings when I have them.
Now mix up the cake as the directions say, spread on top of the pineapples, bake as directed, and when done, let cool about 5 minutes and turn out onto a cookie sheet.