How to Make It
In a large pot, combine the cannellini beans with the carrots, celery, onion, bay leaves, garlic head, bouquet garni and 1/2 cup of the olive oil. Add 6 quarts of water and bring to a boil. Simmer the beans over low heat until tender, about 1 hour; generously season the beans with salt about 10 minutes before they are done. Let cool.
Meanwhile, preheat the oven to 375°. On a rimmed baking sheet, toss the bread crumbs with 1/2 cup of the olive oil and bake, stirring frequently, until golden and crisp, about 8 minutes. Let cool, then transfer the bread crumbs to a bowl and toss with the chopped parsley, sage and rosemary.
Using the side of a chef’s knife, mash the minced garlic to a paste with a generous pinch of salt. Scrape the garlic paste into a small bowl and stir in the Dijon mustard. Stir half of the garlic-mustard mixture into the toasted bread crumbs.
Drain the beans, reserving 1 cup of the cooking liquid; discard the carrots, celery, onion, bay leaves, garlic and bouquet garni. Transfer the beans to 2 large, shallow baking dishes. Whisk the vinegar and the remaining 1/2 cup of olive oil into the remaining garlic-mustard mixture, then stir in the reserved bean cooking liquid. Pour the mixture over the beans and stir. Sprinkle the bread crumbs on top and bake on the top shelf for 15 minutes, until hot and crusty. Drizzle with olive oil and serve warm.