1 (8 oz.) can crushed pineapple, drained
1/4 c. pineapple syrup
2 Tbsp. plus 1 tsp. cornstarch
1 (16 oz.) can whole cranberry sauce

Blend syrup and cornstarch in saucepan. Stir in pineapple and cranberry sauce. Cook, stirring constantly, until thickened and boiling. Boil and stir for 1 minute. Fill layers and top of cake.