In a medium saucepan over medium heat, melt the butter. Add minced garlic and sauté for 30 seconds until fragrant.
Pour in the heavy cream, stirring constantly. Let it simmer gently for 2-3 minutes (do not boil).
Gradually whisk in the grated Parmesan cheese until fully melted and smooth.
Add salt, pepper, and nutmeg (if using). Continue stirring for 2-3 minutes until the sauce thickens to your desired consistency.
Remove from heat. Toss with cooked fettuccine or your favorite pasta. Garnish with fresh parsley.