1. Fill a large pot with water, add a generous amount of salt, and bring it to a boil.
2. Cook the rotini pasta based on the package instructions (usually 9-11 minutes) until al dente.
3. Before draining the pasta, reserve about 1 cup of pasta water to adjust the sauce consistency later.
4. In a large skillet, heat olive oil or butter over medium-high heat.
5. Add ground beef to the skillet and break it into smaller crumbles while cooking. Stir occasionally to ensure even browning.
6. Cook the ground beef for 5-7 minutes or until it is browned and fully cooked.
7. Drain any excess fat from the skillet to avoid creating a greasy sauce.
8. Reduce the heat to medium and add minced garlic to the skillet with the cooked beef.
9. Sauté the garlic for about 1 minute, stirring constantly, to release its aroma without burning.
10. Sprinkle all-purpose flour over the beef and garlic mixture, stirring well to incorporate it evenly.
11. Slowly pour in the milk while stirring constantly to create a smooth mixture.
12. Bring the skillet’s contents to a gentle simmer and stir for 2-3 minutes until the mixture thickens into a creamy sauce.
13. Add the grated Parmesan cheese, Italian seasoning, salt, and pepper to the sauce mixture, stirring well until smooth and cheesy.
14. Add the cooked rotini pasta to the skillet and toss to coat the pasta evenly in the garlic Parmesan sauce and beef.
15. Use the reserved pasta water to adjust the consistency of the sauce if it becomes too thick.
16. Simmer everything together for 1-2 minutes to allow the pasta to absorb the flavors of the sauce.
17. Garnish the dish with freshly chopped parsley for added color and flavor, if desired.
18. Serve the Easy Beef and Rotini in Garlic Parmesan Sauce hot, paired with a green salad or garlic bread for a wholesome meal.