1. Heat oven to 350°F. Lightly coat inside of 4 individual 2-cup baking dishes with nonstick cooking spray.
2. Stir together 1 tablespoon corn syrup and 1 tablespoon melted butter in each of 4 baking dishes. Sprinkle each with 1/4 cup toffee. Center pineapple rings on toffee and place cherries in centers.
3. Beat softened butter and sugar in small bowl until blended. Add rum and egg, beating well. Stir together flour and baking powder; add alternately with milk to rum mixture, beating until smooth. Spoon about 3/4 cup batter into each prepared dish.
4. Bake 25 to 30 minutes or until wooden pick inserted in center comes out clean. Immediately invert onto serving dish; cool slightly before serving. Refrigerate leftovers. Four 4-inch cakes.