1 yellow cake mix, eggs, water, oil, etc
1 can pineapple (large)
1 stick butter
1 c. brown sugar

Drain pineapple into cup measure. Fix cake mix as directed on box but where you add water add pineapple juice and water.

In a small pan melt butter. Add brown sugar until mixture gets thick (but spreadable you may need less or more brown sugar).

Spread brown sugar mixture in bottom of 9 x 13 x 2 inch pan. Dribble, place or spread (depending on type of pineapple) pineapple over brown sugar mixture. Pour cake mixture over pineapple. Cook as directed on box.

When done immediately invert on another pan (larger sometimes I just cover a piece of cardboard with foil).

My family loves this.