Begin by bringing a large pot of salted water to a boil. Add the rigatoni and cook according to package instructions until al dente, about 10–12 minutes. Reserve 1 cup of the pasta water, drain the rest, and set aside.

In a large skillet, heat 2 tablespoons of olive oil over medium heat. Add the diced onion and sauté until it becomes soft and translucent, around 3–4 minutes. Stir in the minced garlic and cook for an additional minute.

Add 1 pound of ground beef to the skillet, breaking it up with a spatula. Cook for 6–8 minutes until the beef is browned, then drain excess grease.

Stir in 2 tablespoons of tomato paste, 1 teaspoon of Italian seasoning, and optional ½ teaspoon of red pepper flakes. Cook for 2–3 minutes to meld flavors.

Pour in 1 cup of beef broth and 2 cups of heavy cream into the skillet. Stir well and bring to a gentle simmer for 5–7 minutes, stirring occasionally until thickened.

Reduce the heat to low and gradually stir in 1 cup of grated Parmesan cheese until melted. Mix in 1 cup of shredded mozzarella cheese until creamy.

Toss the cooked rigatoni into the skillet with the creamy sauce. Add reserved pasta water as needed for desired consistency.

Transfer to serving plates and garnish with freshly chopped parsley or basil. Serve hot.