Boil a large pot of salted water and cook spaghetti until al dente, about 8-10 minutes. Drain, reserving ½ cup pasta water.

In a large skillet, heat olive oil and sear ground beef with Cajun seasoning for 5-7 minutes until browned. Set aside.

Melt butter in the skillet, add minced garlic, and sauté for 30 seconds until fragrant.

Stir in heavy cream, then gradually whisk in parmesan, mozzarella, and cheddar until melted and creamy.

Add cooked spaghetti to the sauce, tossing to coat. Add reserved pasta water if needed.

Fold in seared Cajun beef and simmer for 1-2 minutes to meld flavors.

Serve with parmesan, black pepper, and parsley for garnish.