One challenge imposed by ubiquitous computing of embedded systems is the need for power and energy-efficient implementations, particularly because many of them are operated with batteries. In this sense, tailored application-specific processors can meet the resource requirements of a specific application in the most efficient way. In this paper, we present TailoredCore, a design methodology to generate application-specific processors based on a core architecture implementation. This methodology analyzes the application to be executed and produces a customized RISC-V core with the resources required, while reducing the hardware overhead due to, for instance, instructions and registers not needed. Using TailoredCore, we achieve up to 38% savings in registers and 12% in logic elements when generating cores for five CHStone benchmark applications and implementing them on an FPGA. These savings in the area also correspond to a reduction of the required power and energy.