A cover for a cooking implement, such as a grill, and a method of using such a cover in order to assist in the cooking of food with steam. The cover comprises a raised portion and a reservoir adjacent the raised portion. The reservoir has first and second walls and a bottom therebetween so as to be capable of containing a liquid. The reservoir further has at least one drain hole located below an upper fill level of the reservoir, and the raised portion has at least one vent hole located above the upper fill level. The drain and vent holes are relatively sized so that a liquid contained within the reservoir flows through and exits the drain hole in the form of droplets, which vaporize substantially immediately once outside the drain hole.