Slice a sliver off the bottom of each peppers, so they stand up. Slice about 1/2-inch off the tops of bell peppers and scoop out the seeds. Chop the tops from around the stem, if desired.
Preheat the air fryer to 380°F for 5 minutes.
Stand the pepper shells up in the air fryer basket. Cook until mostly tender, about 10 minutes. Pour out any accumulated liquid from inside peppers.
While the peppers cook, warm the oil in a large nonstick skillet over medium heat. Add the onion and peppers. Cook, stirring occasionally, until softened, about 5 minutes. Increase the heat to medium-high and add the beef, garlic, and Italian seasoning. Cook, stirring often, until browned and crumbly, about 4 minutes.
Stir in the diced tomatoes, tomato sauce, salt, and pepper. Bring to a boil over medium-high heat. Cook, stirring occasionally, until slightly thickened, about 5 minutes. Remove from the heat and stir in the rice. Let cool slightly. Fold in 1 cup of the cheese.
Spoon 1 cup of filling into each pepper. Top each with 1 tablespoon of cheese.
Air fry at 380°F until the cheese is melted and browned, about 2 minutes.
Video
Notes
Preheating is a good idea. Air fryers don’t technically have to be preheated, but I find that the timing is more consistent when I do preheat them.
Repurpose any extra filling! Depending on the size of the peppers, you may have some filling left over. You can save it to make stuffed peppers again later in the week, or you can use it to top chips for nachos! Stir in a little taco seasoning and black beans for extra flavor when reheating the filling.
Make ahead. Feel free to cook the beef and rice filling and assemble the peppers up to 3 days ahead of time, then air fry them when you’re ready for dinner!
Shred your own cheese. It both tastes better and melts better.