Preheat the oven to 500 degrees F (260 degrees C). Season the roast with salt, pepper, garlic powder, and onion powder; and place in a roasting pan or baking dish. Do not cover or add water.
Place the roast in the preheated oven. Reduce the temperature to 475 degrees F (245 degrees C). Roast for 21 minutes (seven minutes per pound) then turn off the oven and let the roast sit in the hot 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 F (65 degrees C). Carve into thin slices to serve.