Sauté aromatics:Heat olive oil in a large skillet over medium heat. Add the chopped onion and cook until softened, about 3–4 minutes. Stir in garlic and cook for another 30 seconds.
Brown the beef:Add ground beef to the skillet. Season with salt and pepper. Cook until browned, breaking it up with a spoon. Stir in dried oregano, red pepper flakes (if using), and tomato paste. Cook for 1–2 minutes until the tomato paste darkens slightly.
Add pasta and liquids:Stir in orzo, crushed tomatoes, and beef broth. Bring the mixture to a boil, then reduce the heat and simmer.
Simmer until tender:Let it cook uncovered for 10–12 minutes, stirring occasionally, until the orzo is tender and most of the liquid is absorbed.
Finish with cream:Stir in the heavy cream and cook for 1–2 more minutes. Taste and adjust seasoning if needed.
Serve:Garnish with chopped fresh basil and a sprinkle of Parmesan cheese, if desired.