The natural sweetness of the plantains enhances the flavor of this Puerto Rican dish.
- Preheat oven to 350°F.
- Brown the ground beef in a large pot. Drain the fat and add the remaining filling ingredients. Cook over medium heat for 5 minutes. Set aside.
- Boil the peeled plantains in 10 cups of water until soft, then drain. In a large bowl, mash the plantains, then add the olive oil. Mix well, making it into a soft dough.
- In a separate bowl, beat the egg whites until they are foamy.
- Spread half of the plantain dough in an 11" × 14" baking pan. Add a layer of the meat filling, egg whites, and half of the green beans.
- Repeat these layers, and top with a final layer of plantains and egg whites. Sprinkle with the mozzarella cheese.
- Bake for 20 minutes. Cut into 12 servings.