Butterscotch Filling Be The First To Review By Anonymous recipe Comments | 0 Favorites | 95 Print This filling complements chocolate cakes especially well. This recipe makes enough to fill one 2 layer cake. Butterscotch Filling Ingredients 1/2 cup packed brown sugar1/4 cup corn starch1/4 teaspoon salt1/2 cup water1 tablespoon butter Instructions 1 Mix together the brown sugar, corn starch, salt, and water in a small saucepan. Bring mixture to a boil, and stir constantly for 1 minute. Remove from heat, and add the butter or margarine. 2 Allow the mixture to cool slightly, and spread between layers.