Boil potatoes until tender. Mash with 3 tablespoons butter or margarine and milk. Season with salt and pepper to taste. Set aside.
Saute onion and carrots in olive oil until soft. Stir in ground turkey, parsley, thyme, and garlic. Once turkey is almost browned and broken up, add zucchini and mushrooms. Salt and pepper to taste. Drain. Stir in flour.
Divide meat mixture into two whole wheat pie crusts. Sprinkle cheese over meat, if desired. Spread green beans over the cheese. Spread potatoes over all with a spatula; the mashed potatoes act as the top crust. Dot with butter.
Bake at 375 degrees F (190 degrees C) for 30 minutes, or until potatoes have browned slightly.
