Slice the bell peppers in half lengthwise and remove the seeds and white membranes. Lightly brush the interiors with olive oil and sprinkle with a touch of salt and pepper.

In a skillet, heat olive oil over medium-high heat. Add the diced onion and cook until soft and translucent, about 3-4 minutes. Add the ground beef and cook, breaking it up, until no pink remains. Drain excess grease.

Add minced garlic to the meat and cook for less than a minute. Stir in tomato paste, tomato sauce, Italian seasoning, salt, pepper, and oregano. Simmer for 5 minutes.

Remove from heat. Stir in cooked rice and half of the shredded cheese until well combined.

Spoon the mixture into each pepper cavity, mounding slightly. Preheat air fryer to 375°F (190°C) and place stuffed peppers in the basket, cooking in batches if necessary.

Cook at 375°F for 12 minutes or until peppers are fork-tender and filling is heated.

Sprinkle remaining cheese over the peppers and cook for another 3-5 minutes until cheese is melted and bubbling.

Remove peppers carefully and let rest for 2 minutes before serving.