Most undernourished preschool-aged children have low hemoglobin and albumin levels, which leads to a higher risk of infections, including COVID-19. This study was designed to determine whether potato almond orange cookies increase weight, hemoglobin, and albumin) in undernourished preschool-aged children during the COVID-19 pandemic. A pre-post intervention study was conducted with 30 subjects during 8 weeks in which hemoglobin and albumin levels were recorded at the beginning and end. Education on balanced nutrition was provided to mothers using leaflets, flipcharts, and videos. The results showed increases in weight (0.4 kg), height (1.98 cm), hemoglobin level (0.1 g/dL), and albumin level (0.1 g/dL) accompanied by a significant increase in weight, height, and the Z-score index for weight for age, whereas those for Hb and albumin levels were not. Energy, carbohydrate, fat, vitamin C, vitamin E, and iron intake increased significantly. Further, there was a significant difference in mothers' knowledge of balanced nutrition and COVID-19 at the end of the study. Thus, high levels of cookie consumption increased the weight of underweight preschool-aged children. Future studies may wish to consider examining the issue using stunted, wasted, and anemic preschool-aged children as the research subjects.