Bring a large pot of salted water to a boil and cook rotini according to package directions until al dente. Reserve 0.5 cup of pasta water, then drain the pasta.

In a large skillet over medium-high heat, brown the ground beef until fully cooked (approximately 7-8 minutes). Drain any excess fat from the skillet.

Reduce the heat to medium and add the butter to the skillet with the beef. Once melted, add the minced garlic and sauté for 60 seconds until fragrant.

Stir in the heavy cream, onion powder, salt, and black pepper. Bring the mixture to a light simmer.

Gradually add the cheddar and parmesan cheeses, stirring constantly until the cheese is fully melted and the sauce is emulsified.

Add the cooked rotini to the skillet and toss to coat every spiral thoroughly.

Adjust the sauce consistency by adding the reserved pasta water 1 tablespoon at a time if needed.

Serve immediately while the cheese sauce is at peak viscosity.