An electromagnetic cooking device includes a cavity in which a food load is placed, a plurality of RF feeds for introducing electromagnetic radiation into the enclosed cavity, and a controller configured to detect asymmetries and select rotations that compensate for the asymmetries; select a heating target including a plurality of resonant modes that are rotated using the selected rotations in the preceding step; generate a heating strategy based on the heating target to determine a sequence of desired heating patterns; cause the RF feeds to output a radio frequency signal to thereby excite the enclosed cavity with a selected set of phasors for a set of frequencies; and monitor the created heating patterns based on the forward and backward power measurements at the RF feeds to use closed-loop regulation to selectively modify the sequence of resonant modes into the enclosed cavity based on the desired heating patterns as monitored.