The phrase "cook a storm" refers to someone who is cooking with a lot of enthusiasm and vigor. Consequently, antonyms for this phrase would be someone who is cooking with less zeal and energy. Some possibilities include "half-heartedly cook," "meekly prepare," "timidly simmer," or "undercook." Alternatively, one could create an antonym contrasting the word "cook" with "serve," suggesting that someone who is "serving a meal" may be doing so without putting much effort into the cooking itself. Regardless, antonyms for "cook a storm" would point to a lack of energy and enthusiasm in the kitchen.