A rotor blade according to an exemplary aspect of the present disclosure includes, among other things, a platform, an airfoil that extends radially from the platform, a first cooling core that extends at least partially inside the airfoil, a second cooling core inside of the platform, a first cooling hole that extends circumferentially between a mate face of the platform and the second cooling core, a second cooling hole that extends between a gas path surface of the platform and the second cooling core, the second cooling core radially disposed between the gas path surface and a non-gas path surface, and the second cooling core circumferentially disposed between the first cooling core and the mate face. A method of cooling a blade is also disclosed.