1. Preheat oven to 350 and grease a 1-1/2 quart casserole dish with nonstick cooking spray. Set aside. 2. In a fry pan, add butter, onion and garlic. Heat over medium heat until onions are tender. 3. Stir in flour, salt and pepper and milk. Continue to heat over medium heat until thick and bubbly. 4. Place half of the potatoes into the bottom of the prepared casserole dish and top with half of the mixture. Repeat. Cover tightly with foil. 5. Bake for 40 minutes. Remove foil (discard) and sprinkle with parsley. Bake for an additional 15 minutes. Let stand 5 minutes before serving.