Objective To develop a novel functional rice cake with enhanced nutritional value and improved flavor, achieving a health-conscious modification of traditional rice cake formulation.Methods Japonica rice flour was used as the base substrate, supplemented with co-fermentation of plant lactic acid bacteria and brewing yeast. The composite ratio of flaxseed meal (7%) and chickpea meal (5%) was optimized by single-factor experiments combined with principal component analysis (PCA). The effects of the improved formulation on product quality, nutritional composition, in vitro digestion characteristics, antioxidant activity, and flavor profile were systematically evaluated.Results The optimized rice cake maintained whiteness while total phenolic content increased threefold, and DPPH and ABTS⁺ radical scavenging rates doubled. Slowly digestible starch and resistant starch content significantly increased, with an estimated glycemic index (eGI) reduced to 53.758, meeting low glycemic index food standards. Nutritional analysis revealed a 1.105 g/L increase in protein content, with significant decreases in cholesterol and starch. Gas chromatography-mass spectrometry (GC-MS) combined with orthogonal partial least squares discriminant analysis (OPLS-DA) demonstrated that the formulation effectively reduced fermentation acidity and introduced characteristic flavor compounds such as isobutanol.Conclusion The flaxseed-chickpea composite technology significantly enhances the nutritional value and antioxidant properties of the rice cake, optimizes digestive metabolic performance, and improves flavor characteristics.