Preheat oven to 375 degrees. Chop cauliflower and boil in salt water just like you would when making mashed potatoes. When fork tender, drain the water off and add butter, sour cream, Parmesan cheese and a sprinkle of salt, pepper and garlic. Mash well and set aside. While cauliflower is cooking, brown the ground turkey (or chop leftover roasted turkey) drain off any fat drippings and place meat into a deep sided casserole dish which has been sprayed with cooking spray. To layer the rest of the items, pour the chicken broth over the turkey. Layer the veggies over the meat and broth. Next spread the mashed cauliflower over the veggies, taking care to bring the cauliflower all the way to the edges of the casserole dish, making a seal which will keep anything from bubbling out and over the dish. Now top with the shredded cheese and bake for 30 to 40 minutes, or until the internal temperature reaches 145 degrees. The cheese will be golden brown and bubbly. Serves 4.