In a large, deep skillet, heat the olive oil over medium heat. Once the oil is hot, add the diced onions and sauté for 5-6 minutes until they start to soften. Add the ground beef to the skillet, breaking it apart as it cooks. Continue cooking until no pink remains. Drain any excess grease and return the skillet to the heat.

Keeping the heat at medium, stir in the garlic, basil, oregano, salt, red pepper flakes, and flour. Cook for 1 minute, stirring constantly to evenly coat the ingredients.

Pour in the tomato sauce and beef broth, stirring to combine. Bring the mixture to a boil, then reduce to a simmer and cook for 15 minutes.

Meanwhile, cook the Rotini pasta according to package instructions. Drain and set aside.

Add the heavy cream and cooked pasta to the sauce, stirring well to combine. Mix in the grated cheddar cheese and continue stirring until the cheese is fully melted and incorporated.

Garnish with fresh or dried parsley if desired, and serve immediately.