In a pot, start browning the ground beef over medium/high heat. Season it with salt and pepper. Once cooked, remove it from the pot and drain any excess fat.

Reduce the heat to medium. Add the diced shallot, drained diced tomatoes, and minced garlic to the pot. Cook until the garlic is golden and the shallot has softened.

Once the garlic is golden, mix in the tomato paste. Cook for another minute or two.

Add the cooked ground beef back into the pot. Pour in the marinara sauce and combine everything together. Heat until warm, then taste and adjust seasoning if necessary.

Preheat your air fryer to 350°F.

Cut the tops off the bell peppers and remove the stems and seeds.

Spoon the ground beef mixture into each bell pepper, filling them to the top but leaving space for cheese.

Place the stuffed peppers in the air fryer and cook for 7 minutes.

Remove them, sprinkle cheese on top, and cook for an additional 3 minutes, keeping an eye on the cheese to prevent burning.