1. Season the Chateaubriand generously with salt and pepper and let rest at room temperature for about 10 minutes. While it is resting preheat a 10 inch cast iron skillet over high heat until it is searingly hot, and preheat your oven to 225 degrees 2. Quickly sear all sides of the beef and then remove from the pan. 3. Truss the beef, and then stick all of the sprigs of thyme and rosemary under the trussing. Place in a roasting pan and roast in the oven for about 45 minutes or until internal temperature is 127 degrees. Remove from oven and cover with foil. 4. For the sauce, while the roast is cooking, melt 2 T butter in a sauté pan then sauté the shallots in there until translucent. 5. Add red wine and vinegar and bring to a simmer and reduce until it is a syrupy consistency, about 10 minutes. 6. Add beef stock and thyme and then simmer until it is reduced to about 1 cup of liquid.