Over the years, portobello mushrooms have become a favorite of mine. They can accent a dish or be the dish, they can be cut up, stuffed or used in place of meat on a sandwich. Really, the only trick to portobellos is to remove the gills on the underside. If left in, they will discolor the dish they are used in as they are very black and that color transfers. The easiest way to do this is use a serrated spoon – like a grapefruit spoon and simply scoop them out like this. After this they are ready to be used however you wish.