Add 1 pound ground beef to the skillet, breaking it up with a spoon. Cook until browned and no longer pink, about 5-6 minutes. Drain excess grease if necessary. Season the beef with 1 teaspoon Italian seasoning, 1 teaspoon salt, 1/2 teaspoon pepper, and 1/4 teaspoon red pepper flakes (if using).

Push the beef mixture to one side of the skillet and add 1 tablespoon double-concentrated tomato paste to the center. Let it cook for about 1 minute, stirring occasionally, until slightly caramelized. Mix it into the beef and onion mixture.

Stir in 1 cup frozen peas and let them heat for 1-2 minutes. Add 1 cup heavy cream and 1/2 cup chicken or beef broth, stirring well to combine. Bring the mixture to a gentle simmer and let it cook for 3-4 minutes.

While the sauce is simmering, cook 1 pound cheese tortellini according to the package directions, until al dente. Drain and set aside.

Add the cooked tortellini to the skillet, stirring to coat it in the creamy tomato sauce. Gradually stir in 1/2 cup freshly grated Parmesan cheese until melted and the sauce thickens slightly. Taste the dish and adjust seasoning if needed.

Garnish with 2 tablespoons fresh parsley, chopped (optional), and extra Parmesan cheese, if desired. Serve warm.