Prep the peppers: Heat oven to 400°F (200°C).
Slice bell peppers in half lengthwise and remove seeds and membranes. Rub the outsides lightly with olive oil, sprinkle with a pinch of salt, and place cut-side up in a baking dish.
Par-bake: Bake peppers for 10–12 minutes to soften slightly. This helps them cook through without getting soggy later.
Cook the filling base: While peppers bake, heat 1 tsp olive oil in a large skillet over medium.
Sauté onion for 3–4 minutes until translucent. Add garlic and mushrooms; cook 2 minutes more.
Brown the turkey: Add ground turkey, breaking it up with a spatula. Season with oregano, basil, red pepper flakes, salt, and black pepper.
Cook until no longer pink, about 6–8 minutes.
Add sauce and “toppings”: Stir in pizza sauce, chopped turkey pepperoni, and olives. Simmer 2–3 minutes to thicken slightly. Taste and adjust seasoning.
Boost the protein and creaminess: Remove skillet from heat and fold in cottage cheese and half the mozzarella.
The mixture should be thick and scoopable.
Fill the peppers: Spoon the mixture into each pepper half, packing it in. Top with remaining mozzarella.
Bake to finish: Return to oven for 12–15 minutes, until peppers are tender and cheese is melted.
Broil for bubbles: Optional but recommended—broil 1–2 minutes for browned, bubbly cheese. Watch closely.
Garnish and serve: Let rest 5 minutes.
Sprinkle with chopped parsley or basil. Serve hot.