Prepare all of the ingredients. Start water boiling for pasta. Preheat oven to 400Fdeg.
In a frying pan over medium heat, add sausage and cook for 10 minutes, turning occasionally. Remove from heat and cut in half then slice each link.
Add pasta to boiling water and cook for half of cooking time listed on packages. Drain in colander.
In a 20x12x2 aluminum tray, add bell pepper, garlic, onion, crushed tomatoes, tomato, puree, broth, red pepper flakes, fennel seed, half of Italian seasoning, and parmesan cheese. Cut half of pepperoni into quarters and add to tray. Stir to combine.
Stir in pasta and cover with 1½ cup mozzarella cheese and remaining Italian seasoning. Cover with foil and bake in oven for 30 minutes.
Remove foil, top with remaining pepperoni and sprinkle with remaining mozzarella. Return to oven and bake for 10 minutes more. Let stand 10 minutes before serving.