1. Preheat oven to 350 degrees F.

2. Chop your 1/4 cup onion and half cup bell peppers for filling. Set aside.

3. With a paring knife, cut off the top of the pepper. Discard or save to top your pepper bowls with. Discard the seeded core. Place the peppers on a parchment lined oven safe dish. Bake for 10 minutes or until soft. (You don't want them to be wrinkly yet at this point because you're going to bake them again as a last step.)

4. While the whole peppers are baking, pour your 3 Tablespoons of olive oil and heat in a skillet over medium heat. When the oil is hot, add the diced onions and peppers and cook for 2 to 3 minutes until soft. Add the minced garlic and cook about 1 minute. Add the spinach and cook for 1 minute. Add the 1 lb of ground beef and break it up with a wooden spoon. Stir it into your vegetable mixture and cook for 2 to 3 minutes. Add the tomato paste, chili powder, cumin, salt and pepper. Cook until the meat is mostly browned, about 10 minutes.

5. Divide the meat mixture evenly into your prepared whole bell peppers. Return them to the oven for 7 minutes. Add cheese (optional) and cook another 3 minutes. If you don't add cheese, cook them for a whole 10 minutes before removing from oven. The peppers should be wrinkly, the cheese melted and the meat browned on top.