Combine mustard and mayonnaise, mix thoroughly. Coat chicken with mustard mixture. Combine cracker crumbs and parmesan cheese. Sprinkle cracker crumbs lightly over the chicken. Place chicken in one layer in a 12x16 inch baking pan. Bake in a 325 degree oven for 30 minutes. Drizzle oil over the chicken and continue baking for 1 hour or until chicken is tender.