Step 1 In a large saucepan, combine the beans, onion, carrot, garlic and bouquet garni. Cover with water or stock, bring to a boil and simmer until very tender, about 30 minutes. When the beans are tender, remove the vegetables and bouquet garni and drain the cooking liquid, reserving about one-third cup for pureeing.
Step 2 While the beans are still hot, puree them in a food processor, adding cooking liquid as needed, the lemon juice and olive oil. Puree until smooth. Season with the roasted garlic puree and salt and pepper to taste.