Cooked up a storm is an idiomatic expression used to describe someone who has created a large quantity of food or who has cooked with great enthusiasm and energy. The word "cooked" in this context refers to preparing ingredients by heating them. Antonyms for this expression would be to "cook minimally," indicating someone who has only prepared a small amount of food or who has put in only the minimum effort required to cook. Another antonym could be "food mediocrity", indicating someone who has cooked poorly or without any passion or enthusiasm. Ultimately, the antonyms for "cooked up a storm" all imply a lack of effort or enthusiasm in the kitchen.