- 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
- Quickly sear all sides of the beef and then remove from the pan.
- 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.
- For the sauce, while the roast is cooking, melt 2 T butter in a sauté pan then sauté the shallots in there until translucent.
- Add red wine and vinegar and bring to a simmer and reduce until it is a syrupy consistency, about 10 minutes.
- Add beef stock and thyme and then simmer until it is reduced to about 1 cup of liquid.