Preheat oven to 350 degrees Fahrenheit. Prepare an 8"x8" baking dish by coating it with nonstick cooking spray. In a large skillet, saute green pepper in olive oil. Add Italian sausage to skillet and crumble and cook completely. Stir in marinara sauce and 1 1/2 c. cheese. Add pasta to the sauce mixture and toss to coat completely.

Pour into prepared baking dish, cover with foil and bake until warmed through and bubbly, about 30 minutes. Five to ten minutes before it's done, remove the foil, sprinkle the remaining 1/2 c. mozzarella cheese and 1/3 c. parmesan cheese on top, then return to oven, uncovered, for last few minutes of baking time.