Fettucini Alfredo with Chicken and Mushrooms

5 T. + 1 T. butter
2 cups heavy cream
1 tsp minced garlic
1/4 tsp pepper
3/4 cup shredded mozzarella cheese
1/2 cup grated parmesan cheese
2 pounds cooked, chopped chicken
1 1/2 cups sliced mushrooms
1 tsp dried chopped parsley
12 oz fettucini, prepared according to package directions

Melt 5 T butter in a heavy saucepan.  Add cream, garlic, and pepper. Just before the cream mixture comes to a boil, add the parmesan and mozzarella cheeses.  Allow to simmer and thicken, stirring regularly.   In a small skillet, melt the other T of butter.  Saute the mushrooms until tender.  Place the fettucini on a platter.  Top with chicken and mushrooms. Stir the parsley into the alfredo sauce then pour over the fettucini, chicken and mushrooms.   Serve immediately.