1 box vanilla cake mix (made according to box directions)
1 (16-20 oz.) can crushed pineapple
1 tbsp. cornstarch
1 tbsp. butter (optional)

Blend juice of drained pineapple with cornstarch and heat until thick. Add drained pineapple, cool.

Make cake mix and pour in 9x12 inch sheet cake pan which has been greased and floured. When cake is half done, drop thick mixture by spoonfuls over cake. Finish baking, cool and enjoy.