Grape “Butter” with Pears and Quinces

Even though sugar became widely available in France in the sixteenth century, it wasn’t until the nineteenth century, when an industrial process for extracting it from sugar beets came into use, that it became a staple most everyone could afford. Fruits are, of course, a natural source of sugar, and grapes, common in France, were crushed when ripe and boiled down to a concentrated juice that would set into a stiff pastelike jelly that could be eaten with bread or be used as a sweetener in o