Make Twenty Minute Marinara Sauce according to recipe instructions.
Dice onion and set aside.
Mince garlic and set aside.
Cook pasta according to package instructions.
Preheat oven to 425°.
Heat large cast iron skillet over medium heat and add oil.
Add onion and sauté for 7 minutes until onion is tender.
Add garlic and sauté for 1 minute.
Add ground beef, salt, pepper, Italian seasoning and cook for 10 minutes, breaking pieces up, until meat is fully cooked.
Add pasta, red pepper flakes, and marinara sauce to skillet. Mix until well combined and spread into an even layer.
Sprinkle top with mozzarella and parmesan cheese.
Top with pepperoni.
Bake for 5 minutes until cheese melts.
Garnish with fresh basil.