Start With the Base: Heat a large deep pot over medium heat and add olive oil. Once warm, add onion, carrot, and celery. Stir often and cook for about 5 minutes until everything softens and smells sweet.
Brown the Beef: Add ground beef to the pot. Break it apart with a spoon and cook until no pink remains. Let it sit briefly so it browns slightly, which adds deeper flavor.
Add Garlic and Tomato Paste: Stir in minced garlic and tomato paste. Cook for about 1 minute while stirring. This step deepens the tomato flavor and removes the raw taste.
Season the Sauce: Sprinkle in dried oregano, dried basil, salt, and black pepper. Stir well so the spices coat the beef and vegetables evenly.
Build the Sauce: Pour in diced tomatoes and beef broth. Stir and bring the mixture to a gentle simmer. Let it bubble for about 5 minutes so the flavors come together.
Add the Orzo: Stir the orzo directly into the pot. Lower the heat slightly and cover. Let it cook for about 10 minutes, stirring once or twice to prevent sticking.
Finish the Texture: Remove the lid and continue cooking for another 3 to 5 minutes until the orzo turns tender and the sauce thickens.
Finish With Cheese: Turn off the heat and stir in grated Parmesan. Let it melt fully, then top with fresh basil before serving.
