The aim of this study was to use purple sweet potato powder to develop a recipe for a nutritional cookie with an optimal composition of ingredients and texture, in order to acquire strong preference responses by all age groups in sensory tests. Wheat flour was partially substituted with purple sweet potato powder to reduce the wheat flour content of the cookies. Measurements were made and analyzed according to the Response Surface Methodology technique, which showed 16 experimental points including 3 replicates for the purple sweet potato powder, sugar, and butter. The compositional and functional properties of the sample were measured, and the values obtained were applied to a mathematical model. A canonical form and perturbation plot showed the influence of each ingredient on the final product mixture. The results of sensory evaluations showed very significant values for flavor (P＜0.0071), texture (P＜0.0306), taste (P＜0.0190), and overall quality (P＜0.0142). Instrumental analysis showed significant values for hardness (P＜0.0027), yellowness (P＜ 0.0061) and spread ratio (P＜0.0001). The optimal compositional ratios were determined to be 21.75 g for the purple sweet potato powder, 37.05 g for the sugar, and 60.59 g for the butter.