In a large soup pot or Dutch oven, heat over medium-high heat and add the lean ground beef. Cook for 5-6 minutes, allowing it to brown undisturbed, until fully cooked and no longer pink. Break it into smaller pieces with a wooden spoon for even cooking.

Add the chopped onion to the pot and continue cooking for an additional 5 minutes. Stir occasionally until the onion becomes tender and translucent. Mix in the minced garlic, crushed red pepper flakes, and Italian seasoning, sautéing for 1 minute until fragrant.

Introduce the uncooked orzo pasta to the pot, stirring gently with the beef and aromatics. Allow the pasta to toast slightly for about 1 minute. Ensure everything is well combined before moving on to the next step.

Pour in the tomato sauce, beef broth, heavy cream, and Worcestershire sauce, stirring to combine all the ingredients. Bring the mixture to a gentle bubble over medium heat, allowing it to cook for about 10 minutes, stirring often.

Once the orzo has absorbed most of the liquid and is tender, remove the pot from heat. Stir in the freshly grated Parmesan cheese and packed baby spinach, mixing until the spinach wilts and the cheese melts into the sauce.

Cover the pot and let it sit for about 3-5 minutes to thicken slightly. Taste and season with salt and pepper as desired before serving hot.