Pre-heat oven to 400 F.

Peel the plantains, place them on a baking sheet and rub them with butter.

Bake the plantains for 20 minutes, then turn them and bake for another 15 minutes or until golden on both sides.

Meanwhile, make the filling: In a medium pan, heat the olive oil over medium-low heat. Add the and cook onion until soft. Add the chopped garlic and cook until almost golden.

Add the cumin, salt and pepper. Add the ground beef, beef broth and tomato sauce. Cook for about 20 more minutes.

Remove the plantains from the oven, make a horizontal slit on the middle of each plantain, and stuff them with the meat mixture.