Mixed Vegetable Stew

One thinks of a stew most often as a variety of foodstuffs cooked together in sauce; the Lyonnais barboton, whose preparation, but for the absence of meat, is that of a simple meat stew (potatoes lent relief by onion, garlic, often a bit of tomato, and a bouquet garni, gently cooked in a lightly roux-thickened bouillon), or the genial ratatouille, whose vegetables, intact but purée-tender, are cloaked in a syrupy reduction of their own abundant juices, correspond nicely to tha