Preheat over to 400 degrees. Drain oysters well. Generously grease a shallow 1 1/2-quart casserole dish. Sprinkle half of the cracker crumbs over the bottom. Lay half of the oysters on top of the crumbs, then sprinkle with half of the onions, parsley, lemon juice, salt, pepper and Worcestershire sauce. Dot generously with butter and pour on half of the cream and milk. Repeat layers but save the remaining crumbs for the top. Add a dash of Tabasco if desired before covering with the crumbs. Bake for 35 minutes. Serve hot.