Remove the roast from the fridge 30 minutes before roasting.
Place the roast on a sheet pan or roasting pan.
Mix all the salt and spices together in a small bowl. Then rub them all over the meat with your hands.
Preheat the oven to 225 degrees.
Insert a probe of a thermometer into the deepest part of the meat. Put roast in the oven.
While the roast cooks, combine softened butter and the chopped rosemary. Place this in the freezer to harden.
Roast until the meat in the oven until it reaches 120 degrees. Then remove from the oven.
Raise the oven temperature to 500 degrees. Cut your frozen rosemary butter into pieces and place on top of the roast.
Return the roast to the oven and roast until it's 5-8 degrees from your final desired temperature (see notes). It will carry over the rest of the way.
Allow the roast to rest for at least 15 minutes. You can wrap it in foil to keep it hot.
Carve off thin slices of the roast and cut the roast against the grain on your plate.