Ingredients
Heat oven to 350. Coat a 9x13" baking pan with cooking spray. Spread marshmallows evenly over bottom. Prepare cake according to package directions. Pour batter over marshmallows. Spoon cherries evenly over batter.
Bake 45 to 50 minutes. Here's what happens as it bakes: The cherries sink to the bottom and the marshmallows rise to the top and form a thin topping that will brown and be bubbly. Insert toothpick in center of cake to check for doneness.
