Spiced jelly was a kind of preserve made by Benjamin Sisko, presumably a fruit or vegetable derived food ingredient flavored with some type of spice. He had given some to Jadzia Dax, who ate it on galzak. Sisko was supposedly offended that she did not eat it on toast, or at least on an English muffin. (TNG - Slings and Arrows eBook: Enterprises of Great Pitch and Moment)