Bring a large pot of water to a boil. Season with enough salt so that water tastes mildly of salt. Add pasta and cook until al dente. Drain well.
Preheat oven to 375°F.
Heat a large skillet over medium-high heat. Add the ground beef, onion, garlic, Italian seasoning and red chili flakes; cook for 4 minutes. Add the peppers and cook further for 5 minutes or until the beef is browned and cooked through. Drain excess grease.
Reduce heat to medium. Add the beef broth and mix to combine. Cook for 1-2 minutes.
Add the marinara sauce and pizza sauce. Stir to combine, using a silicon spatula. Bring to a simmer and cook for 1 minute.
Reduce the heat to low and add in Parmesan cheese.
Add the pasta to the skillet and stir to combine.
Transfer to a lightly greased 10.5x7.5-inch casserole dish .
Top with mozzarella cheese and then place pepperoni slices on top.
Cover with non-stick aluminum foil and bake for 10 minutes. Then uncover and bake for 15 minutes or until the cheese is fully melted. To brown the top more, broil at 450F for 1 minute.
Garnish with fresh basil or parsley.
Serve and enjoy!