Preheat and prep: Heat your oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish.
Sauté veggies: Warm 1 tbsp olive oil in a large skillet over medium heat.
Add the onion and bell pepper with a pinch of salt. Cook 4–5 minutes until softened. Stir in garlic and cook 30 seconds more.
Transfer to a bowl.
Brown the turkey: Add the remaining 1 tbsp oil to the skillet. Crumble in the ground turkey, season with salt, pepper, oregano, and basil. Cook, breaking it up, until no pink remains and excess moisture cooks off, about 6–8 minutes.
Build the sauce layer: Reduce heat to low.
Stir the sautéed veggies back into the turkey. Pour in the marinara and red pepper flakes. Simmer 2–3 minutes to let flavors mingle.
Taste and adjust salt and pepper.
Layer in the dish: Spread the turkey-marinara mixture evenly in the prepared baking dish. Sprinkle half the mozzarella over the top, followed by half the Parmesan.
Add the “pizza” toppings: Scatter olives (if using), then arrange most of the turkey pepperoni slices on top. Finish with the remaining mozzarella and Parmesan.
Tuck a few extra pepperoni slices on the very top for crisp edges.
Bake: Bake uncovered for 18–22 minutes, until the cheese is melted and bubbling around the edges.
Broil for crispness (optional): Turn on the broiler for 1–2 minutes to brown the cheese and crisp the pepperoni. Watch closely.
Rest and serve: Let it rest 5–10 minutes so the layers set. Sprinkle with chopped basil or parsley.
Slice and serve hot.