In the United States, catering services constitute about $8.6 billion annually. The main objective in managing large catered events is centered around ensuring good customer satisfaction while minimizing food wastage. Achieving this management objective is challenging because of some of the key characteristics of such service systems such as long setup time, time-varying demand, and complex customer food preferences. Industry practice heavily relies on the experience of individuals with little use of model-driven decision-making for planning such events. This paper takes a service system engineering approach for event catering by developing an analytical framework for decision-making by event planners to determine kitchen capacity, temporary storage capacity for warmers, and staffing level for buffet service. The proposed model is distribution-free and provides intuitive visualization for decision-making. As a practical case study, the model is applied to a large catered event with an attendance of about 10,000 over three hours.