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.
The result is an osso buco you'd be hard-pressed to distinguish from the labor-intensive classic. Put flour into a shallow wide bowl. Season lamb shanks with salt and pepper; dredge through flour until coated, shaking off any excess flour. Heat a large skillet over medium heat; add butter and heat until foaming.
Preheat the oven to 325°. In a large skillet, heat 2 tablespoons of the vegetable oil. Add 4 of the lamb shanks, season with salt and pepper and cook over moderate heat until well browned all over, about 10 minutes. Transfer the shanks to a large roasting pan.
Keto osso bucco stew is the perfect winter warming dish. The slow cooked meat is fall of the bone and is so soft and tender. The reduced sauce is so rich and full of flavour with the tomato sauce and the stock adding a fullness of flavour. The mushrooms add texture and a richness.