Preheat oven to 275 degrees F.
Season lamb osso bucco liberally with salt and pepper and set aside on a plate. In a heavy-bottomed roasting pan over medium-high heat, heat olive oil on stove top. Carefully place the osso bucco in the hot roasting pan and sear all sides, until nicely browned. Once seared on all sides, remove from pan and set back onto plate. Using the same pot with the lamb drippings in the bottom, add carrots, celery, onions, and garlic. Saute for approximately 10 minutes using a wooden spoon to scrape the lamb drippings off the bottom of the pan and to caramelize the vegetables. Once caramelized, add tomato paste, coat the vegetables with the paste, and brown slightly, about 5 minutes. Add the red wine to deglaze the pan, scraping the drippings off the bottom of pan using a wooden spoon. Reduce the wine by half and add the Lamb Stock and thyme. Season with salt and pepper. Place the seared osso bucco back into the pan. Change to high heat and once the stock starts to boil, put roasting pan into the oven. Cook the osso bucco for about 2 hours until it is fork tender, almost falling off the bone. You will want to turn the osso bucco every half hour so that it cooks evenly and does not burn on the bottom.
When finished, take the lamb out of the sauce and set aside. In a blender, blend the sauce until the vegetables are pureed. Place about a 1/4 cup of sauce into the bottom of each serving bowl, top with osso bucco and drizzle with a little more sauce. It is best served with roasted carrots, onions, and potatoes.
Preheat oven to 400 degrees F.
In a large roasting pan, roast lamb bones in the oven until dark brown. On a sheet tray, roast carrots, celery, and onion in the oven until browned as well. Place the bones and vegetables in a 4-gallon stock pot. Add 2 gallons cold water, salt and pepper, and bay leaves, if desired. Bring to a boil over high heat and then turn down to a simmer over medium-low heat. Simmer for 4 to 5 hours to get the best results.
If using lamb base, roast vegetables as explained above. In a 4-gallon stock pot, add 2 gallons water and whisk in lamb base. Add the roasted vegetables and bring to a boil. Turn down the heat to medium-low and simmer for approximately 1 hour.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.