Boil a large pot of salted water. Cook rotini for 9–11 mins until al dente. Reserve 1 cup pasta water, then drain.

Heat 2 tbsp olive oil in a skillet over medium-high. Cook ground beef for 5–7 mins until browned. Drain excess fat if needed and set beef aside.

Add minced garlic to the same skillet. Sauté for 1 min until fragrant.

Sprinkle flour over beef and garlic, stir. Gradually add milk, stirring to prevent lumps. Simmer for 2–3 mins to thicken.

Stir in Parmesan, Italian seasoning, salt, and pepper. Cook for 1–2 mins until cheese melts and sauce is smooth.

Combine drained pasta with sauce in skillet. Adjust consistency with reserved pasta water if needed.

Garnish with fresh parsley and serve immediately.