Soak beans in 4 cups (1 L) of cold water overnight; drain. In large pot, bring 8 cups (2 L) water, beans, onions and garlic to boil; reduce heat and simmer until beans are tender, 1 hour.

With slotted spoon, remove 1 cup (250 mL) of the beans; set aside. To pot, add watercress and parsley; simmer for 5 minutes.

In blender or using immersion blender, purée soup until smooth, adding enough water to make 7 cups (1.75 L). Return to pot and add kale, reserved beans, salt and pepper; bring to boil. Reduce heat; cover and simmer until greens are tender, about 40 minutes.

Ladle soup into bowls and drizzle with olive oil.

Makes 4 servings.

Tip: If you're short on time, you can use this quick method for soaking beans: Place beans in saucepan; pour in enough water to come 1 inch (2.5 cm) above beans. Bring to boil; boil for 3 minutes. Remove from heat, cover and let stand for 1 hour; drain and continue with recipe.

Tip: Instead of dried beans, you can use 1 can (19 oz/540 mL) white kidney beans, drained and rinsed. Add to 8 cups (2 L) water with onion and garlic and simmer until garlic is tender, 20 minutes.