-
1
Place the beef in a large roasting pan and season all over with salt, rubbing it into the meat and bones.
-
2
Combine the mustard, rosemary, onion flakes, and pepper and stir to mix.
-
3
Rub the spice mixture all over the beef to coat evenly.
-
4
Cover loosely and place in the refrigerator overnight, or for up to 2 days.
-
5
About 2 hours before cooking, remove the meat from the refrigerator and let come to room temperature.
-
6
Move a rack to the lower third of the oven and preheat the oven to 450F.
-
7
Roast the beef for 20 to 25 minutes, until it begins to brown and sizzle.
-
8
Reduce the temperature to 325F and continue to cook for about 2 hours, until an internal thermometer inserted in the middle of the roast registers 110F to 115F for rare, or 20 to 25 minutes more, until the thermometer reads 120F to 125F, for medium-rare (the temperature will continue to rise another 5 degrees while the meat rests).
-
9
Remove the roast from the oven and let sit, loosely covered, for about 30 minutes before carving.
-
10
To carve, remove and discard the chine bone (see Know-how, page 203) and slice the meat to the desired thickness.
-
11
Arrange on a serving platter and serve warm with the horseradish sauce on the side.
-
12
Combine the sour cream, horseradish, heavy cream, hot sauce, and rosemary in a bowl and stir to combine.
-
13
Season with salt and pepper to taste and refrigerate in an airtight container until ready to serve, or for up to 4 days.
-
14
The chine bone is the flat bone that lies just below the rib bones, and the added flavor it imparts is well worth the effort of removing the bone after roasting.
-
15
(If youd rather not deal with it, ask the butcher to remove the bone and tie it back onto the roast.
-
16
If you do this, you will need to reduce the cooking time by 30 to 40 minutes.)
-
17
After the roast is done, place it on a cutting board, loosely covered, and let rest for about 15 minutes.
-
18
To remove the chine bone, use a sharp boning or slicing knife to slice from the end of the bone to the back of the roast, cutting as close as possible to the bone.
-
19
Place the roast on the board, rib side down, and slice into thick portions, cutting between the ribs.
-
20
For thinner portions, remove the rib bones by placing the roast on its bottom, where you removed the chine bone (with the ribs standing up), and use a sharp knife to slice between the rib bones and the meat, cutting as close to the bone as possible, to remove the roast in one piece.
-
21
Place the roast on the cutting board, rib side down, and slice into portions across the grain to the desired thickness.
-
22
Cut only the number of slices you want to serve immediately; this will keep the meat moist.
