Preheat your oven to 400 degrees f.
Place your prepared peppers cut side up onto the baking dish as shown. Lightly spray or spritz with avocado oil and sprinkle with sea salt and pepper. Roast in your preheated oven for about 10-12 minutes.
Heat a large skillet over medium-high heat.
Add the ground meat and cook until no longer pink, stirring and mincing with a wooden spoon. Drain off excess grease.
Season lightly with sea salt and pepper.
Add the onions, garlic, and mushrooms, and cook for 5-6 minutes longer.
Sprinkle with chili flakes and remove from heat.
Stuff your peppers evenly with the meat mixture and top with cheese.
Return to the oven for 8-10 minutes, or until the cheese melts.
Garnish with parsley and serve while hot.