Preheat the oven to 200°. Line baking sheets with foil and coat with oil.
Using a sharp knife cut both ends off the plantain. This will make it easy to grab the skin of the plantains. Slit a shallow line down the long seam of the plantain; peel only as deep as the peel. Remove plantain peel by pulling back.
Place plantains on tray and lightly spray, bake for a about 15 minutes, turn and bake on the other side for another 15 minutes or until golden brown and tender.
While the plantains are baking, add 2 tablespoon of oil to a saucepan, followed by the onions, garlic and tomatoes. Let it simmer for about 5-7 minutes, stirring frequently to prevent burning, add about 2 tablespoons or more of water if needed.
Then, add beans and continue cooking for about 5-7 or more minutes.
Finally add pepper and parsley, add spices and finally the spinach
Remove the baked plantains from oven and cool for a couple of minutes.
Then make a horizontal split in the plantains and stuff with equal amounts of the bean mixture and stuff with equal amounts of the bean mixture. Serve warm