Place the roast in the preheated oven. Reduce the temperature to 475 degrees. Roast for 21 minutes (seven minutes per pound) then turn off the oven and let the roast sit in the oven for 2 1/2 hours. Do not open the door at all during this time!
Remove the roast from the oven, the internal temperature should have reached at least 145 degrees. Carve into thin slices and serve.