If using dried beans, as in the original recipe: Put the beans in a saucepan and add cold water to cover. Bring to a boil and boil for 5 minutes, then remove the pan from the heat. Let the beans cool, covered, in the cooking water for 1 hour (no longer or they will be too soft). Add more water to cover the beans, if needed, along with the clove-studded onion, bay leaf, 7 of the garlic cloves and the 1 tablespoon salt. Bring to a boil, then reduce the heat, cover and simmer until the beans are just tender to the bite; do not overcook or the cassoulet will be mushy.

Alternatively, use canned beans, as they will stay much firmer in the finished dish: Open 3 cans of cannellini beans and pour into a bowl with their liquid. Add 1 chopped garlic clove and 1 bay leaf. Let stand while you prepare the lamb.

Cut 2 of the garlic cloves into slivers, make incisions in the lamb shanks and stuff the garlic into them. Rub the shanks with 2 teaspoons of the rosemary and the 2 teaspoons salt. 

In a deep, heavy fry pan or sauté pan, melt 3 tablespoons of the butter with 3 tablespoons of the oil. Add the lamb shanks and brown on all sides, turning with tongs and sprinkling with pepper as they cook. Add the remaining rosemary, the wine and broth. Bring to a boil, then reduce the heat, cover and simmer for 1 hour.

In another fry pan or sauté pan over medium heat, warm the remaining 3 tablespoons oil. Add the onions and cook, stirring occasionally, until lightly browned. Reduce the heat to low, cover and cook until the onions are soft.

Preheat the oven to 350°F.

Drain the beans, reserving the liquid. Finely chop the remaining garlic cloves. Transfer the lamb shanks to a plate and remove as much fat from the cooking liquid as possible. 

Layer half of the beans in an 8-quart braising pan or casserole. Top with a layer of the onions and the chopped garlic. Put the lamb shanks on top. Add the remaining beans and the lamb cooking liquid. If there is not enough liquid to cover the shanks, add some of the reserved bean liquid and more water or wine. Lay the bacon slices on top. 

Transfer to the oven and cook for 1 hour. In a fry pan over medium heat, melt the remaining 2 tablespoons butter. Toss in the bread crumbs and remove from the heat. Sprinkle the crumbs over the top of the cassoulet. Return to the oven and cook until the crumbs are golden, about 20 minutes more. Serve directly from the pan.

Alternatively, after browning the lamb shanks, add the rosemary and liquids. Cover and braise them, on their own, in a 350°F oven for a total of 2 hours. When the shanks are cool enough to handle, remove the meat from the bones. Assemble the meat with the beans, onions, garlic, liquids and bacon slices as instructed above, then cook in the 350°F for 30 minutes. Top with the buttered bread crumbs and cook for 20 minutes more.