Celine Guervilly University of Leeds We study the formation of long-lived large-scale vortices in rotating Boussinesq convection in planar geometry. These vortices, which are always cyclonic in the explored parameter range, extent through the whole depth of the computational domain and grow to the largest horizontal size permitted. We will discuss the domain of existence of these vortices, the possible mechanisms by which they form, and how they affect the heat transfer through the system.