Mushroom Casserole

3 pounds mushrooms
1 (8 oz.) bag poultry stuffing mix
½ stick margarine or butter
1 (8 oz.) pkg. Velveeta cheese
1 (5 oz.) can evaporated milk
½ cup boiling water

Clean and slice mushrooms. Cook 5 minutes in water to which a spoonful of vinegar has been added. Drain. Place in a 9 x 13 inch baking dish. Slice cheese and place on mushrooms. Prepare stuffing with margarine melted in boiling water. Spoon over cheese layer. Pour milk over stuffing. Cover with foil. Bake at 350 degrees for 30 minutes.