Preheat oven to 350*.
On stovetop, cook and drain fettuccine (or spaghetti) noodles.
Place in greased casserole pan.
Top with diced chicken or turkey.
In a saucepan melt butter and cooked sliced onions and mushrooms until tender.
Add flour and reduce to low heat.
Slowly add broth until boiling.
Remove from heat and add heavy cream,
Add salt, pepper and nutmeg to cream mixture.
Add to cooked fettuccine mixture and mix together.
Top with Parmesan and bread crumbs.
Cover and cook in 350 oven 30-40 minutes.
Remove foil and cook an additional 5-7 minutes until top is bubbly.
Top with chopped parsley and serve.