Combine warm water, sugar, and yeast. Allow to sit for 10 minutes until the yeast foams. Add flour, salt, oil, melted butter, and sourdough starter (discard, it does not need to be fed. This is optional but definitely adds to the flavor). Knead by hand or with mixer. Form into 2 rectangles and roll into long loaves. Place on cookie sheet that has been sprinkled with corn meal. Oil tops and place food service wrap on top. Place in refrigerator and refrigerate overnight. Bake for 20 minutes at 425 degrees. Beat egg white with 1 tablespoon water and brush over top of loaves. Return to the oven and bake for an additional 5 minutes or until cooked through.