Clean and soak white beans overnight, or at least 8 hours.
Dredge lamb pieces in mixture of flour, salt and pepper. In a large Dutch oven, brown lamb meat in oil, until browned on all sides. Remove from pot and reserve. Add garlic and leeks with 1-2 tbsp oil and sauté 8-10 minutes until soft and beginning to brown. Add thyme and heat for 1 minute more.
Rinse and drain beans, add to pot with browned lamb, cayenne pepper, lemon juice and 3 cups of chicken broth. Cover, bring to a near-boil, then simmer for 50 minutes to 1 hour - until beans are soft. Liquid should cover stew during cooking; add more chicken broth if needed.
Remove 1/2 c of white beans from stew. Puree in blender or processor and set aside. Add tomato, chard and basil to pot and simmer 10 more minutes. Add pureed white beans back and warm through.
Season with salt and pepper to taste, garnish with lemon wedge and fresh basil sprig if desired. Serve with warm, crusty bread for a delicious meal!
4 generous servings