Flakes are instant breakfast meals, primarily produced from mono-cereals (corn, wheat, rice, and/or oats), processed with added flavor and fortified with vitamins and minerals. They are one of the several forms of cold cereals that are consumed immediately after mixing with milk, yogurt, or fruit. In this study, value-added instant flakes were developed, characterized and optimized; from blends of corn, millet, and soybean. A three-component constrained optimal (custom) mixture experimental design, with 30 randomized experimental runs, was employed for the formulation. The formulation design constraints were: corn flour (30% - 45%), millet flour (10% - 25%), and soybean flour (5% - 20%). Other components of the formulation, which were kept constant, were: water (19%), sugar (8%), malt (2%), egg (3%), sweet potato extract (3%), ginger (2%), and moringa seed powder (3%). The formulated flakes were analyzed and evaluated for the proximate, physicochemical and sensory characteristics using standard procedures. The result of the numerical optimization gave optimized instant flakes with an overall desirability index of 0.637, based on the set optimization goals and individual quality desirability indices. The optimal instant flake was obtained from 30.5 % corn flour, 11.2 % millet flour, 18.3 % soybean meal. The quality properties of this optimal instant flake were: 1.83 % moisture content, 9.05 % fat content, 1.74 % ash content, 2.66 % crude fibre, 38.0 % crude protein, 46.7 % carbohydrate, 420 kcal energy value and 6.28 overall acceptability. The result of the study showed that the formulated instant flakes were of high quality and that improving the nutritional quality of flakes is possible through grain-to-grain composite formulation. It is recommended that further study be carried out on the formulation of nutritionally improved instant flakes using other nutritionally rich grains and legumes such as groundnut, sesame seed, melon seed etc. Enrichment of flakes with protein-rich sources will result in flakes product with improved nutrient quality that meets the consumer’s dietary needs.