The early summer version of this jam was made from the heirloom Springcrest, an old-fashioned cling peach from Andy Mariani's orchard, infused with true saffron. Later in the season, it's made with a combination of the superb Baby Crawford and Kit Donnell peaches, also from Andy's orchard. The jam is cooked with the noyaux, you might even find one (or bits of one) in the jar if you're lucky.
Nigella Lawson called this jam the best jam she's ever tasted. So there.