1. A portable, rechargeable vessel for collecting, storing, and recovering thermal energy for cooking, comprising: a structure defining a well and an open-top portion at the top of the well; a phase-change material, wherein the phase-change material is disposed in the well, the phase-change material having a phase change at a temperature in the range of 150-700° C.; one or more thermally-conductive fins interleaved in the phase-change material; and a thermally-conductive heat transfer plate disposed at and substantially covering the open-top portion of the structure, in direct thermal contact with the one or more fins, thereby allowing the transfer plate to directly exchange thermal energy with the phase change material, wherein the transfer plate comprises a solar absorbing material having a solar absorptivity of at least 0.75 disposed at the top surface of the transfer plate in substantial thermal contact with the one or more fins through the transfer plate and configured to heat the phase change material by conducting solar-adsorbed energy to the phase change material through the transfer plate and fins.