This study aimed to analyze the effect of adding roselle calyx powder (Hibiscus sabdariffa L.) on the sensory characteristics and nutritional content of florentine bar cookies. The study employed a Completely Randomized Design (CRD) with three roselle powder concentration treatments, namely R1 (2 g), R2 (5 g), and R3 (8 g) per 120 g of florentine flour. Sensory evaluation was conducted by 25 semi-trained panelists using a five-point hedonic test, while nutritional content analysis was performed on the selected sample using the SNI 01-2891-1992 method. The Kruskal–Wallis test results showed that the addition of roselle powder had a significant effect on taste (p < 0.05) and texture (p < 0.05), but no significant effect on aroma (p > 0.05) and color (p > 0.05). Formulation R1 achieved the highest acceptance, with taste, aroma, texture, and color scores of 4.48 ± 0.81, 4.00 ± 0.80, 4.04 ± 0.82, and 4.04 ± 0.77, respectively. Nutritional analysis indicated that florentine bar cookies per serving (26 g) provide 132.6 kcal of energy (6% AKG), 7.29 g of fat (11% AKG), 2.69 g of protein (4% AKG), and 13.87 g of carbohydrates (4% AKG). Formulation R1 with the addition of 2 g of roselle powder represents the optimal concentration, producing a product with the best balance between functional value and sensory acceptability, and therefore has potential to be developed as an innovative bakery product based on local ingredients.