From America's Test Kitchen
Pork tenderloin has many advantages that make it an ideal candidate for the grill: It’s quick-cooking, extremely tender, and has a uniform shape which allows for even cooking. But this cut is also mild and lean, making it prone to drying out. Stuffing this roast solves these problems by adding flavor and moisture. Pounding and rolling the tenderloins created more surface area for the filling and helped prevent leaks. Pulsing bold ingredients—such as olives, sun-dried tomatoes, and porcini mushrooms—in a food processor produced an intense paste that stayed put and didn’t ooze out. A two-level fire, with the coals spread over half the grill, allowed the pork to cook evenly without drying out, while a sprinkling of sugar on the outside of each tenderloin boosted browning significantly.
Makes about 1 cup, enough for 2 tenderloins