Pecorino Romano, an aged hard cheese made from sheep’s milk, is a marvelously flavorful grating cheese. Braciola refers to a rolled cut of meat. In this case, the long, slow cooking method tenderizes flank steak. The knobby celery root, also known as celeriac, may be the world’s ugliest vegetable, but the taste—like a combination of celery and parsley—is delicious raw as well as cooked. Prepare the Celery Root Purée shortly before the beef is done and keep the purée warm. This dish is suitable for Induction because you discard the carrot used in the braising sauce before serving and it includes a side dish.
Preheat the oven to 300ºF.
Season the meat with salt and pepper
In food processor, combine the parsley, Pecorino Roman and garlic. Add 2 tablespoons of olive oil, while pulsing slowly, until a paste forms.
Add a thin layer of paste to the flank steak, leaving about an inch on all edges. Roll into a log and tie with butcher twine.
In a large skillet or sauté pan over medium-high heat, add remaining olive oil and sear the meat on all sides until brown. Remove meat from the pan.
Add the onion to the pan and sauté until translucent; then add the carrot and celery. Add the tomato paste and let the mixture brown slightly. Slowly add the beef broth and bring to a boil.
Transfer the meat to a deep casserole dish and add the braising liquid. Cover the casserole dish with foil and the lid to retain the steam. Place the dish in the oven and cook for 2 hours, or until the meat is fork-tender.
Shortly before the meat is done, bring the water to a boil in a medium saucepan. Lower to a simmer, add the celery root and cook until fork-tender, about 5 minutes. Remove from the heat and strain the celery root, reserving the liquid.
Place the celery root and cream in a food processor and purée until smooth. If necessary, add reserved liquid to make a creamy consistency. Season to taste with salt and pepper and add a few drops of truffle oil (if using). Set aside and keep warm.
Remove the meat from the casserole dish. Strain the remaining liquid, discarding the vegetables, and reduce the liquid over medium heat, stirring, until the sauce coats the back of a spoon.
Remove the twine from the meat and slice into 1-inch-thick pieces.
Divide the slices evenly among four serving plates. Spoon the sauce over the steak and serve alongside the purée.