Cook the beans in unsalted water until tender, about 1 to 1 1/2 hours. Drain, reserving the liquid. Preheat the oven to 350° F - 180C). Stir the apples, sugar, cinnamon, vinegar, and salt into the beans. Transfer to an ovenproof dish and just cover with some of the reserved liquid. Cover with a lid or foil and bake for 35-40 minutes.
Servings: