Boil a large pot of salted water and cook rotini pasta according to package directions until al dente. Reserve 0.5 cup pasta water before draining.
In a large skillet, heat olive oil over medium-high heat. Add ground beef and cook until browned, breaking it into small crumbles. Drain excess fat.
Reduce heat to medium. Add minced garlic to the beef and sauté for 1 minute until fragrant.
Pour in heavy cream and bring to a gentle simmer.
Stir in the grated parmesan cheese, salt, pepper, and oregano. Whisk until the cheese is melted and the sauce has thickened slightly.
Add the cooked rotini to the skillet and toss to coat thoroughly.
Adjust sauce consistency using the reserved pasta water if needed.
Garnish with fresh parsley and serve immediately.