Cookies have come in wide varieties and had different appearances over the years, but they are primarily light brown circular cookies with chocolate chips baked into them. A common drink to dip them in is milk.
During a series of fulfilling his many requests, Mr. Krabs is forced by Squidward to give him a plate of cookies, which he does, but Squidward criticizes them for tasting nothing like his mother made them. This prompts Mr. Krabs and SpongeBob to go to Mrs. Tentacles' house and try to get her homemade cookies.
They are successful in doing so and deliver them to Squidward, who actually appreciates them this time for being just like how his mother used to make them.