Preparation Soak beans in cold water to cover by 2 inches in a bowl at room temperature at least 8 hours, or quick-soak (see cooks' note, below). Drain well in a colander. Cook pancetta, onion, and garlic in oil in a wide 6- to 8-quart heavy pot over moderate heat, stirring occasionally, until browned, about 8 minutes. Add tomatoes with juice, beans, broth, water, cheese rind, salt, and pepper and simmer, uncovered, until beans are tender, 45 minutes to 1 hour. Discard cheese rind and stir in chestnuts. Transfer 2 cups soup to a blender and purée until smooth (use caution when blending hot liquids), then return to pot. Stir in kale and simmer, uncovered, stirring occasionally, until leaves are tender, 10 to 15 minutes. Stir in thyme. Cooks' notes:·Soup can be made 3 days ahead and cooled completely, uncovered, then chilled, covered. Reheat, thinning with water as necessary. ·Beans can be soaked at room temperature up to 12 hours. ·To quick-soak beans: Cover beans with cold water by 2 inches in a 4- to 5-quart pot and bring to a boil, uncovered. Boil beans 2 minutes, then remove from heat and let stand, uncovered, 1 hour.