Prep the peppers: Slice the tops off the bell peppers and remove seeds and membranes. If they wobble, trim a thin slice off the bottom so they stand upright.
Brush the outsides lightly with olive oil.
Preheat the air fryer: Set to 360°F (182°C). This helps the peppers start cooking right away.
Sauté aromatics: In a skillet over medium heat, add a drizzle of olive oil. Cook the onion for 3–4 minutes until softened.
Stir in garlic and cook 30 seconds, just until fragrant.
Brown the beef: Add ground beef to the skillet. Cook, breaking it up, until no longer pink, about 5–6 minutes. Drain excess fat if needed.
Build the filling: Stir in crushed tomatoes, tomato paste, Italian seasoning, smoked paprika, salt, and pepper.
Simmer 2–3 minutes to thicken slightly. Fold in the cooked rice. If the mixture seems too thick, add a splash of broth or water.
Taste and adjust: Season with more salt and pepper if needed.
You want a well-seasoned, spoonable filling.
Stuff the peppers: Spoon the beef mixture into each pepper, packing it in gently. Leave a little space at the top for cheese.
Air fry, round one: Arrange peppers in the air fryer basket so they don’t touch. Cook at 360°F (182°C) for 10–12 minutes, until the peppers begin to soften and the filling is hot.
Add cheese and finish: Sprinkle mozzarella (and Parmesan, if using) on top.
Air fry another 3–5 minutes, until the cheese is melted and bubbly with light golden spots.
Rest and garnish: Let peppers rest 3 minutes to settle. Garnish with parsley and serve.