1/2 c. butter, melted in 9x13 inch pan
1 c. brown sugar, mix with butter
1 (15-20 oz. can pineapple in juice, drained (save juice), spread over above
1 yellow cake mix (mix according to directions using reserved juice as part of water)

Pour over pineapple. Bake at 350 degrees for 40-45 minutes.