In a 4-quart pot, combine the beans, onion, celery, green onions, garlic, ginger,
and pepper to taste. Add 6 cups of water and bring to a boil, stirring occasionally
Lower the heat, cover, and simmer for 45 to 60 minutes.
Place the spinach leaves in a sauté pan at medium-high heat. Stir for 2 to 4
minutes. Chop the cooked spinach; set aside.
Stir the spinach into the soup and mix well. Spoon sour cream into the center
of each serving, and sprinkle with cilantro.