Bring a large pot of salted water to a boil. Add the beef tortellini and cook according to package instructions until al dente, about 3-5 minutes. Drain and set aside.
While the tortellini cooks, heat olive oil in a large skillet over medium-high heat.
Add the ground beef to the skillet and cook, breaking it up with a spoon, until browned and cooked through, about 6-8 minutes.
Add the chopped onion and minced garlic to the skillet with the beef. Cook until the onion is softened and translucent, about 3-4 minutes.
Stir in the crushed tomatoes, beef broth, dried oregano, dried basil, and crushed red pepper flakes. Season with salt and freshly ground black pepper to taste.
Bring the sauce to a simmer, reduce the heat to medium-low, and cook for 10 minutes, stirring occasionally, until the sauce thickens slightly.
Add the cooked tortellini to the skillet and gently toss to coat them evenly with the sauce.
Remove from heat and sprinkle grated Parmesan cheese and chopped fresh parsley over the top before serving.