Preheat your oven to 375°F and prepare a baking dish.
Slice the tops off the bell peppers, remove the seeds and membranes, and set aside.
Heat the olive oil in a large skillet over medium heat and sauté the diced onion and minced garlic until they become translucent and fragrant.
Add the ground beef to the skillet, breaking it apart with a spatula, and cook until it is fully browned.
Drain any excess fat from the skillet, then stir in the cooked brown rice, tomato puree, sea salt, black pepper, smoked paprika, and cumin.
Spoon the beef and rice mixture into the hollowed bell peppers, pressing down gently to pack them tightly.
Place the stuffed peppers upright in the baking dish and pour a small amount of water into the bottom of the dish to create steam.
Cover the dish tightly with foil and bake for 30 minutes, then remove the foil and bake for an additional 10 minutes until the peppers are tender and the tops are slightly golden.
Garnish with fresh chopped parsley before serving hot.