Beat egg in a bowl until yolk and white are mixed. Place flour on a flat plate. Remove chicken from marinade and place in bowl. When pieces are coated, add them one at a time to floured plate, flipping them to get a dusty cover. Alternatively, you can pour the flour in a paper bag and shake 2 pieces at a time. If using butter, remove sheet from oven; you can optionally mix a little oil with the butter. If not, simply spray a parchment lined baking sheet with non-stick spray. Place chicken pieces on sheet.