1. Melt butter in a medium saucepan over medium heat. Add cream cheese and garlic, stirring with wire whisk until smooth.
2. Add heavy cream, a little at a time, whisking to smooth out lumps. Stir in Parmesan, salt and pepper. Remove from heat once sauce thickens a little. Add more cream as needed if the sauce gets too thick.
3. Toss with hot fettuccine to serve.