In a large bowl, combine the ground beef, bread crumbs, Parmesan cheese, parsley, garlic, dried oregano, dried basil, red pepper flakes, salt, and pepper. Mix well.

Shape the mixture into meatballs, about 1 inch in diameter.

In a large skillet, heat some olive oil over medium heat. Add the meatballs and cook until browned on all sides, about 5 minutes. Remove the meatballs from the skillet and set aside.

In the same skillet, add the chopped onion and minced garlic. Cook until softened, about 5 minutes.

Add the crushed tomatoes, dried oregano, dried basil, red pepper flakes, salt, and pepper to the skillet. Stir to combine.

Return the meatballs to the skillet, submerging them in the sauce. Simmer for 20-25 minutes, until the meatballs are cooked through.

Serve the spicy meatballs with pasta or crusty bread. Enjoy!