Key-value data structures are an essential component of today's stateful packet processors such as load balancers, packet schedulers, and more. Realizing key-value data structures entirely in the data-plane of an ASIC switch would bring enormous energy savings. Yet, today's implementations are ill-suited for stateful packet processing as they support only a limited amount of flow-state insertions per second into these data structures. In this paper, we present SWITCHAROO, a mechanism for realizing key-value data structures on programmable ASIC switches that supports both high-frequency insertions and fast lookups entirely in the data plane. We show that SWITCHAROO can be realized on ASIC, supports millions of flow-state insertions per second with only limited amount of packet recirculation.