Take the roast out of the refrigerator, discard the packaging, and pat it dry with a paper towel.
Make a paste with the seasoning ingredients using a knife, mortar and pestle, blender or food processor.
Apply the seasoning paste evenly to all sides of the roast. Insert the temperature probe, then place the roast in the cooking vessel. I like to use a Dutch oven.
Let the roast sit at room temperature for 1 hour, if desired.
Cook
Preheat the oven to 450°F.
Place the seasoned roast in the oven, uncovered, for 15 minutes. This browns and sears the meat.
Without opening the oven door or covering the roast, reduce the oven temperature to 300°F. Cook for 60 minutes, or until the internal temperature reaches 130–135°F. See the notes for medium and well-done temperatures.
When the roast reaches the desired internal temperature, remove it from the oven, place it on a plate, and tent it with foil. Let it rest for at least 10 minutes.
Gravy (optional)
Place the roasting dish on the stove over medium heat. Add the butter and let it melt, then whisk in the flour. Add the water ¼ cup at a time, whisking out any lumps and letting the mixture thicken before each addition. Taste and add salt or pepper if needed.
Cut the Roast
Remove the cooking string.
Separate the bone section from the loin and set it aside.
Slice the loin against the grain into pieces ¼ inch thick or thinner. Serve with gravy.
Notes
Serving guide: A 5-pound bone-in roast makes approximately 8 generous servings. Actual yield varies with roast weight, bone size, slice thickness, appetites and side dishes.Medium Rare 145∘F (Take out of the oven at 135∘F)Medium 160∘F (Take out of the oven at 150∘F) Well Done 170∘F (Take out of the oven at 160∘F)