1. Preheat oven to 350 degrees F. Spray a 6-cup casserole pan with vegetable cooking spray.
2. In a medium bowl, mix together flour, baking powder, and salt and set aside. In a glass measuring cup, mix milk, vanilla, and 1 tablespoon of rum (or 1/2 teaspoon of rum extract) and set aside.
3. In a large mixing bowl, use an electric mixer on medium-high speed to beat together butter and sugar until smooth, about 2 minutes. Add egg and 2 tablespoons of maple syrup and beat until thick and smooth.
4. Add half the flour mixture to the butter mixture and mix on low just until combined. Add milk mixture and blend in. Add remaining flour and mix on low speed until smooth, about 2 minutes.
5. Pour batter into prepared pan. Make the sauce: Stir 1/2 cup of maple syrup and 1 tablespoon of rum (or 1/2 teaspoon of rum extract) into boiling water and pour it over batter. It will look watery, but dont worry magic will happen in the oven.
6. Bake at 350 degrees F for 30 to 35 minutes, until cake has risen and is firm to the touch. A toothpick inserted in the center should come out clean. Cool on a wire rack for a few minutes and serve warm from pan, topped with walnuts, ice cream, or whipped cream, if desired.
Source: Hannaford fresh Magazine, March - April 2009