In a medium saucepan over medium heat, melt 1 cup unsalted butter until fully melted and slightly bubbling.
Stir in minced 4 cloves garlic and cook about 30 seconds until fragrant, careful not to burn.
Slowly add 2 cups heavy cream , whisking constantly. Bring to a gentle simmer.
Gradually add grated 2 cups Parmesan cheese, stirring until fully melted and smooth.
Add1 tsp salt , ½ tsp black pepper , and ¼ tsp nutmeg (if using). Stir until creamy.
Let sauce simmer 2–3 minutes on low, stirring occasionally until thickened.
Pour over cooked pasta, chicken, shrimp, or vegetables. Garnish with extra Parmesan or parsley.