In a large saucepan sauté onion in butter. Add the broth, broccoli stems, 1/2 the potatoes, 1/2 the carrots, celery, pepper, lemon juice, thyme, bay leaf, salt and cayenne. Bring to a boil; reduce heat and simmer (about 15 minutes or until veggies are tender.
Remove the bay leafand purée the veggies in a blender. Return the purée to the pot. Add the remaining potatoes and carrots and cook the soup over low heat for about 10 minutes. When the potatoes and carrots are nearly soft, add the broccoli flowerets to the pot and cook for another 5-10 minutes or until broccoli is tender-crisp.
Add the milk and crab meat and heat, but do not boil. Serve the bisque with croutons.
Servings: