Pull the meat from the bones and reserve bones and slkin for stock. Cut meat into bite sized pieces and reserve for the tetrazzini. Make stock from the turkey bones, skin, etc (see chicken stock video in sauce chapter.)
In a large stock or sauce pan, melt a stick of butter, add diced onions and cook until soft and tender, add garlic, stir. Add flour to form a roux, cook slowly for about 5 minutes to allow the roux to form. (For more Bechamel insight see Bechamel Video in sauce chapter)
Add turkey stock or chicken broth, stir, this should become a tight ball. Add heavy cream a third at a time and stirring constantly with each addition. I use cream to create a rich velvety rich sauce.(you could use half & half or milk for a lighter sauce)
Turn this into mornay sauce by adding Swiss and parmesan cheese. Add sliced mushrooms and season with FGs Steak Spice or salt and pepper. Add turkey and a few green peas for color, stir to combine.
Spray a large casserole dish with pan spray. Arrange cooked spaghetti in the dish. Pour tetrazzini over pasta. Stir to combine pasta and sauce. Top evenly with shredded Swiss and grated parmesan and fresh bread crumbs.
Fresh Bread Crumbs:
Chop day old bread, white bread, hot dog or hamburger rolls in the food processor or use canned Italian bread crumbs.
Bake in a 400-dgeree oven until the casserole is hot in the center and the cheese melts and turns golden brown.