Preheat the air fryer to 360°F (182°C). This helps the peppers start cooking right away and promotes even browning.

Prep the basket. Lightly spray the basket or rub with a small amount of oil to prevent sticking. You can also place a piece of perforated parchment made for air fryers.

Add the frozen peppers. Place them in a single layer, leaving a little space between each one. No need to thaw.

Cook for 15 minutes. This starts to soften the peppers and warms the filling.

Check and rotate. Carefully turn the peppers or rotate the basket to promote even heating. If the tops look dry, brush with a spoonful of marinara or a drizzle of oil.

Cook for another 10–15 minutes. Total time is usually 25–30 minutes, depending on pepper size and your air fryer model.

Add cheese (optional). In the last 3–5 minutes, sprinkle shredded cheese on top and cook until melted and lightly golden.

Confirm doneness. The internal temperature should reach 165°F (74°C). If you don’t have a thermometer, check that the center is steaming hot and the sauce is bubbling.

Rest briefly. Let the peppers sit for 3–5 minutes so the filling settles. Garnish with herbs and a pinch of pepper flakes if you like.

Serve. Spoon a little warm marinara on the plate, set the pepper on top, and enjoy.