Designing a food-energy-water (FEW) nexus framework is critical for the development of future sustainable cities, as well as addressing global concerns of increased demand for natural resources (food, energy and, water). A case study consisting of seven Urban Farms in South Florida is established, with the main objective of providing fresh produce to the local community. Each Urban Farm belongs to a community-scale microgrid system that generates electricity from renewable sources (solar, wind, biomass), and provides electricity to the urban farm and surrounding community buildings. Additionally, a micro-supply chain is established among the seven farms to increase food availability for the local community, combating food deserts and reducing food waste. Following the establishment of a FEW nexus framework, a mathematical programming model is introduced to design and optimize the parameters within the framework. Data inputs used for the model are obtained from the results of a previously developed agent-based model (ABM). The objective of the mathematical programming model is to address the supply and demand balance within the FEW network, and depending on the supply-demand trend, will optimally match supply and demand over time, using indicators such as cost and carbon footprints. In addition, solving the model identifies optimal capacities for renewable energy sources (solar, wind, biomass), as well as the scheduling of the unit commitment and micro supply chain. The results will provide valuable insight into the design of a FEW nexus framework, as well as the interactions that occur between food, energy, and water systems, and allows for the analysis of different policy scenarios and their implications. Once solved, the model provided results for a period of 264 hours, determining optimal operational decisions for power production, electricity for irrigation, and consumption of water that is needed for a combined heat and power (CHP) unit, and for irrigation of crops. The results of the micro supply chain led to the transport of 78,657kg between four farms, and the remaining food waste was converted into biomass energy. The optimal capacities of renewable energy technologies were found, solar with a total capacity of 4,400 kW, and wind with a total capacity of 7,000 kW. The optimal capacity of battery storage systems at each microgrid belonging to each urban farm was found, and this was based on electricity demands, as well as electricity generation capacities. The results of the mathematical programming model led to the optimal design of an urban FEW framework, determining the optimal capacities of renewable energy technologies, battery storage systems, and optimal operation conditions of the FEW nexus.