Put on gloves and generously rub the spice into the flesh on all sides of the roast.
Put the roast on the rack of the roasting pan. Put the probe thermometer in.
Heat the oven to 225 °F (107 °C) and put the roast in.
Set the probe for 127 °F (53 °C) and roast the pork until it reaches that temperature, about 2 hours at 30 minutes per pound or 60 minutes per kg. Make sure the probe reaches 127 °F (53 °C) and does not go past 130 °F (54 °C).
Remove the roast from the oven.
Heat a cast iron grill to at least 500 °F (260 °C). Sear the roast on each side for about 30-60 seconds per side,
Let the roast rest for about 5 minutes off the heat then transfer it to a platter.