No matter how many aromatics you put in, it’s the bones that make the broth. Ideally there will be a ham bone to share the pot with onions, carrots, thyme and garlic, but those of the roasted turkey or goose will do. Bones give the soup a satisfyingly silken quality. If I have time, the beans will be dried, soaked overnight, then boiled and simmered with bay and peppercorns. If not, a can will do.
Care is needed in what else we add, but any fresh greens – cabbage, broccoli, chard and the like – are welcome, as are cooked carrots, parsnips and potatoes. A cold chipolata or two would be like finding buried treasure in your soup and the same with bacon, but this is not the place to chuck anything and everything.
The number one addition would be a lump of rind from the parmesan, which will quietly add a pleasing back-note of umami while it simmers.