Preheat the oven to 350˚F
Use a coffee grinder or a mortar and pestle to coarsely grind peppercorns. Combine the peppercorns and the salt. Rub the tenderloin with 2 tablespoons of the olive oil until coated. Rub the pepper mixture over the tenderloin until generously coated. (You will think you have too much salt and pepper on the meat, but you don’t.)
Using a 14-inch skillet or a stove-top-proof roasting pan or griddle, heat the remaining 3 tablespoons of olive oil over medium-high. Add the tenderloin, and cook on each side until deeply browned, about 5 minutes per side.
Place the tenderloin on a rimmed baking sheet, and bake in the preheated oven until a meat thermometer reaches 130˚F to 140˚F degrees (rare to medium-rare), about 30 to 40 minutes. Allow the meat to stand 20 minutes before slicing. Serve with the Creamy Horseradish Sauce and Vidalia Onion Chimichurri.