Preheat oven to 375 degrees and butter 9" x 13" baking dish; set aside.
Cook spaghetti or linguine according to directions on package. Rinse with cold water; set aside.
Melt butter in large skillet over medium-high heat. Add onions, mushrooms and thyme. Cook until most liquid from mushrooms has evaporated (5 minutes). Add turkey and garlic and cook 3 minutes more then add wine then cook until liquid has evaporated (3−4 minutes). Sprinkle flour over chicken and vegetables, stir to combine then cook for 30 seconds. Add milk then stir to dissolve flour completely, scraping brown bits from bottom of skillet.
Allow mixture to boil then immediately reduce heat to low. Season with salt and pepper and simmer 6−8 minutes—sauce will thicken slightly. Stir in cooked pasta, frozen peas and chopped parsley.
Pour mixture into prepared baking dish and top with grated Parmesan cheese. Bake uncovered 15−20 minutes until bubbly on sides and golden brown on top. Allow to cool 5 minutes before serving and enjoy!
One Last Thing
Choose button mushrooms that are firm and dry with few cracks—store in a paper bag in the fridge for up to one week.