Steps

1. 1

   Preheat the oven to 425°F (220°C) and set an oven rack in the middle position.

2. 2

   Tenderize the beef: In a medium bowl, using your hands, mash the beef with 1 teaspoon of the salt and the baking soda. Let sit for 20 minutes while you continue with the recipe.

3. 3

   Line a 9 x 13-in (23 x 33-cm) baking dish with aluminum foil for easy clean-up, if you like. Place the peppers, cut side up, in the baking dish; drizzle with 1 tablespoon of the oil and sprinkle with the remaining ¼ teaspoon salt.

4. 4

   Roast the peppers for about 20 minutes, until slightly browned and tender-crisp. A bit of liquid will accumulate in the bottom of the peppers; that's okay.

5. 5

   Meanwhile, heat the remaining 2 tablespoons of oil over medium heat in a large nonstick skillet. Add the onion and cook, stirring frequently, until soft and translucent, 3 to 4 minutes. Add the garlic and cook 1 minute more; do not brown. Add the ground beef mixture, chili powder, cumin, and oregano, and increase the heat to medium-high. Cook, breaking the meat up with a wooden spoon, until the meat is browned and almost cooked through, 4 to 5 minutes. Add the tomato sauce and bring to a boil; reduce the heat to medium-low and cook, uncovered, until the meat is cooked through, 2 to 3 minutes. Add the cooked rice and ¾ cup (90 g) of the cheese, and stir until melted. Remove the skillet from the heat.

6. 6

   Remove the peppers from the oven and spoon the meat filling evenly into the peppers. Sprinkle with the remaining ¾ cup (90 g) cheese and place back in the oven. Roast for 10 to 15 minutes, until the filling is hot and the cheese is melted and bubbling, and serve.