Preheat a cast iron grill pan or skillet over high heat.
Rub the roast with the oil, then season roast with salt, pepper, and cumin.
Place the roast into the pan and sear for 8-10 minutes turning until all sides are browned.
Remove the roast from the pan to a plate. Wrap in foil. Allow the roast to rest for 15 minutes.
Preheat the oven to 250 degrees.
Stick a probe thermometer into the center of the roast.
Place the roast back into the cast iron pan. Close the door and attach the probe to the base. Set an alarm to go off at 135 degrees. This should take between 20 to 30 minutes.
Remove from the oven. Wrap the roast in foil and allow at least 15 minutes for it to rest before carving.