In a bowl, soak beans for at least 8 hours, or overnight, in 12 cups (3 L) cold water; drain.
In a Dutch oven or large heavy-bottomed pot, cover beans with 12 cups (3 L) fresh water; add garlic and bring to a boil. Reduce heat, cover and simmer until beans are tender, 45 to 60 minutes. Drain; mash garlic and set both beans and garlic aside.
Return pot to stove; heat oil over medium heat. Cook onions, stirring, until softened, about 3 minutes. Stir in passata, cider, maple syrup, molasses, mustard, vinegar, salt and pepper. Stir in apples, beans and mashed garlic; cover and bake in a preheated 300°F (150°C) oven for 2 hours.
Uncover and continue baking, stirring occasionally, until sauce is thickened, about 1 hour.
Per serving: 522 calories, 20 g protein, 4 g fat (1 g saturated fat), 107 g carbohydrates, 25 g fibre, 0 mg cholesterol, 833 mg sodium