Wash and slice mushrooms thinly.
In a large heavy saucepan, cook the mushrooms in 1/4 cup of the butter over moderate heat, stirring, until most of the liquid they give off has evaporated, stir in the flour and cook the mixture over low heat, stirring for 3 minutes. (if you like - add a diced garlic clove when the mushrooms are almost done)
Add in the milk in a slow stream, the broth and wine, stirring. Bring the mixture to a boil, stirring and simmer the sauce for 5 minutes. Add the turkey, peas, salt & pepper to the sauce and stir. Cook until warmed (about 3-5 minutes)
In a kettle of boiling salted water, cook the spaghetti until it is al dente and drain it well.
In a large bowl combine the spaghetti and the sauce. Stir in 1/3 cup of parmesan cheese. Place pasta in casserole dish.
Melt the remaining tablespoon of butter and mix with bread crumbs and 1/3 cup parmesan cheese. Sprinkle on top of casserole
At this point the tetrazzini may be covered and frozen for up to one month.
Bake the tetrazinni in the middle of a preheated 375 degree oven for 30-40 minutes, or until it is bubbling and the top is golden.
Submitted by: KRINKER29