Preheat the oven to 475F and pour the olive oil in the bottom of a small roasting pan or baking dish, large enough to fit the roast but not much larger.

In a bowl, combine 2 tablespoons of the butter with the salt, mustard, thyme, sugar, and garlic to form a paste.

Place the pork roast in the baking dish and rub all over with the garlic mixture, covering the top and ends of the pork.

Roast the pork for 15 minutes at 475F then reduce the heat to 300F and roast for 15 minutes more (leave the pork in the oven during this time, just adjust the temp at the 15 minute mark).

Remove the pork and test the temperature using a digital or other meat thermometer right at the center of the pork. When the pork reaches 140F internally, remove from the oven. If it needs more time to cook, continue to cook at 300F, checking the temperature every 5 minutes or so.

When the pork has reached 140-145F, remove from the oven and place on a plate or carving board to rest, covered in foil (pork is safe to eat in the 145-155F range, and will continue to cook slightly as it rests out of the oven). While the pork rests, whisk the final tablespoon of butter into the pan drippings.

Carve the pork as desired and return to the baking sheet with the juices and spices. Serve with extra thyme leaves on top. Enjoy!