A method of delivering a liquid heated to a desired temperature under pressure in a microwave oven uses a device having first and second chambers adapted to receive and hold, respectively, a first and second volume of a liquid, a vapor flow path from the first chamber to the second chamber, and a liquid/vapor flow path from the second chamber to a destination outside of the second chamber. The first chamber liquid receives less microwave energy per volume than the second chamber liquid receives. The device is placed on top of a receiving vessel and placed into a microwave oven, which is activated until the first chamber liquid boils and at least partially turns into gas, flows through the vapor flow path into the second chamber, and forces some of the second chamber liquid through the liquid/vapor flow path to the destination outside of the second chamber.