1. Preheat the oven to 375°. Season the lamb with salt and pepper
and roll it into a neat roast. Tie the roast at 1 1/2-inch intervals.
2. In a medium enameled cast-iron casserole, heat 1 tablespoon of
the oil until shimmering. Add the lamb and cook over moderately
high heat until browned all over, about 4 minutes per side.
Transfer the lamb to a plate and pour off the fat in the casserole.
3. Add the remaining 1 tablespoon of oil to the casserole and add
the bacon. Cook over moderate heat, stirring a few times, until
the bacon is lightly browned, about 3 minutes. Add the onions and
cook, stirring a few times, until softened. Add the wine and boil
over high heat until slightly reduced, about 2 minutes. Add the
stock, thyme, garlic and bay leaf. Return the lamb to the casserole
along with any accumulated juices. Cover with a sheet of
parchment paper and the lid. Braise in the oven for 1 hour.
4. Remove the casserole from the oven and transfer the lamb to a
plate. Nestle the potatoes into the liquid. Turn the lamb over and
set it on top of the potatoes. Replace the parchment and the lid
and bake for 1 1/2 hours, until the lamb and potatoes are very tender.
5. Transfer the lamb to a board, cover with foil and let rest for 15
minutes. Discard the thyme sprigs and bay leaf and season the
braising liquid with salt and pepper. Discard the strings and cut the
lamb into thick slices. Serve with the potatoes and braising liquid,
garnished with chives. —David McMillan and Frédéric Morin