Liv's grandma helped us pluck these blackberries from her land, and we've combined them with white peaches from Briermere Farm on Long Island's North Fork. Fall is upon us, and we've pulled out coats and scarves, shocked by the cold wind and beset with the melancholy that the long, wild days of summer are over. This jam preserves the heat and heady sweetness of summer. Tart blackberries and sweet peaches balance each other. Just fruit and sugar, no pectin so you can enjoy the soft set of pure summer in a jar.