Preheat the oven to 375°F and lightly grease a 9x13 baking dish.

Cook the penne in a large pot of salted water until al dente, then drain and set aside.

Heat the olive oil in a large skillet over medium heat. Add the sausage and cook until browned, breaking it up as it cooks.

Add the sliced peppers, diced onion, and minced garlic to the skillet. Cook for 5 minutes until the vegetables soften.

Stir in the marinara sauce, Italian seasoning, salt, and pepper. Simmer for 2 minutes.

Combine the cooked pasta with the sausage mixture in the skillet or a large bowl.

Transfer half the mixture to the baking dish and sprinkle with half the mozzarella and parmesan. Add the remaining mixture and top with the rest of the cheeses.

Bake for 20 minutes until the cheese is bubbly and lightly browned on top.