Cook noodles in boiling salted water; drain and set aside while preparing sauce. In three-quart saucepan, combine milk, evaporated milk, onions, hot pepper sauce, salt and pepper. Simmer for 10 minutes; remove pan from heat; set aside.
In a large skillet, heat 3 tablespoons butter and oil, then sauté mushrooms until lightly browned. Stir in flour and remove pan from heat. Using strainer, add the poaching liquid used to cook the skate. Stir thoroughly, return skillet to heat and cook until sauce is thickened. Stir in sherry.
In large bowl, combine mushroom sauce with noodles, skate and onions. Place in large open casserole dish or in individual oven proof au gratin dishes.
Combine 1 tablespoon softened or melted butter with crumbs; sprinkle over casserole. Bake uncovered at 350 degrees F for 15-20 minutes or until topping is golden brown and sauce is bubbly. Garnish with parsley and serve.
