We investigated the quality characteristics of cookies prepared following the addition of various concentrations of used Hongkuk powder (0%, 1%, 3%, 5%, all w/w) as a substitute for flour. In this study, the moisture content of dough decreased and pH increased by adding Hongkuk powder. The L and b value were decreased significantly, but the a value of cookies increased by addition of Hongkuk powder. The spread factor of cookies was slightly decreased by the addition of Hongkuk powder. The hardness of the control group was higher than that of the cookies prepared with different levels of Hongkuk powder. The result of the sensory score showed that cookies added with 1% Hongkuk powder had higher taste, flavor, and overall acceptability scores than other samples. As a result of this study, the quality of cookies with the addition of 1% Hongkuk powder were the most suitable in terms of its taste, flavor, texture, and sensory properties.