Grass Jelly is an herbal jelly dessert. Delicate and refreshing! It' s made from the roots and stems of the grass jelly herb (called mesona) and typically served as a combination of jelly and liquid. People mostly purchase this dessert canned and pre-made, but once you try this fresh and elegant homemade version, youâ??ll never go back. Enjoy! Grass jelly is an herbal jelly dessert that is very popular in Asia. It' s made by boiling the dried stems and leaves of the Mesona plant (which is part of the mint family). The boiled liquid is dark, warming, and smells amazing.