In a large dutch oven cook pepperoni for a few minutes per side or until crispy.
In the same skillet, brown ground beef, onion, and pepper until no pink remains.
Add garlic and cook for one more minute.
Pour in broth and scrape the bottom of the pan. Then add pasta, marinara, and tomato paste. Bring to boil, reduce to simmer. Simmer for ~15 minutes or until pasta is tender.
Remove from heat. Stir in pepperoni, parmesan, and 1 cup of mozzarella.
Add additional cheese on top, and garnish with additional pepperoni if desired.