1.Bring a large pot of lightly salted water to a boil. Add fettuccine pasta and cook for 8 to 10 minutes or until al dente; drain.
2.In a large skillet melt the butter and add the chopped garlic. Cook on low for about 5 minutes, stirring often, making sure not to burn the garlic.
3.Pour about a 1/4 cup of the heavy cream into a small bowl. Add the egg yolk and beat together; put aside. Pour the remaining cream into the frying pan. Increase the heat to medium-high. As the cream starts to boil; mix rapidly using a whisk. Slowly add the cream/egg mixture. You do not want the egg to curdle. Continue whisking until well blended.
4.Add 1 cup of the Parmesan cheese and continue to mix the cream. Pour in the remaining Parmesan and the parsley, mix until smooth. Immediately remove from stove. Serve over cooked pasta.
