Add the beef and onions to a large Dutch oven, or other heavy bottomed pot set over medium heat. Cook and crumble, until completely cooked through, then strain off all of the excess grease.
1 lb ground beef, 1 yellow onion
Add all of the seasonings to the pot, then stir until evenly incorporated.
salt & pepper, 1 tsp Italian seasoning, 1/4 tsp crushed red pepper flakes
Add the garlic, broth, marinara, milk, and pasta to the pot. Stir everything together until evenly combined, and bring the mixture to a simmer.
1 tbsp minced garlic, 2 cups beef broth, 2 cups marinara sauce, 1/2 cup milk, 2 1/2 cups penne pasta
Cover and simmer gently, stirring occasionally, for 15 minutes- until the pasta's 'al dente', and has absorbed most of the sauce. Remove the pot from heat.
Stir in 1 1/2 cups of cheese until evenly incorporated, then sprinkle the remaining cheese evenly out overtop. Cover and let rest until the cheese has melted.
2 cups shredded mozzarella cheese
Top with pepperoni, serve warm, and enjoy!
mini pepperoni