We love to stir this intensely fruity jam into plain yogurt, so we usually take it off the heat when the mixture is still a bit runny. Cook longer for a thicker consistency. Prep and Cook Time: 25 minutes, plus 2 hours to chill. Notes: To see whether the jam has cooked long enough to thicken to your taste, put a tablespoonful onto a well-chilled plate (you can put the plate in the freezer 20 minutes ahead of time). When it contacts the cold plate, the jam will thicken immediately, giving you a sense of its final consistency.