Strawberry Upside Down Cake

2 cups fresh strawberries, sliced
1 (6 oz) or 2 (3 oz) packages strawberry Jell-O
3 cups miniature marshmallows
1 yellow cake mix, batter prepared as directed on package

Preheat oven to 350 degrees.
Spread sliced strawberries evenly on bottom of 9 x 13 casserole dish.
Sprinkle dry Jell-O over top of strawberries.
Top with mini marshmallows.
Prepare cake mix as directed on package and pour over top of marshmallows.
Bake 40 - 50 minutes.
Cool 15 minutes then turn out onto serving platter (or serve right out of the pan!)
Store cake in the refrigerator.