This method, traditional to Colombia, combines two genius techniques to great effect: grilling in the coals and salt-crusting. Each does wonders for beef tenderloin, which Raichlen admits is "normally a pretty boring piece of meat." Adapted slightly from Planet Barbecue. (Workman Publishing Company, 2010) —Genius Recipes
center cut piece of beef tenderloin, meticulously trimmed of all fat and silver skin (about 6 inches long and weighing 12 to 16 ounces)
salt (we used Diamond Crystal kosher salt)
Special equipment: 1 piece of clean cotton cloth, approximately 16 inches square, dipped in cold water and wrung out slightly
Arrange the cotton cloth on a work surface on the diagonal (like a diamond), so that one corner points down toward you. Spread the salt out on top of the cloth to form a layer 1/4 inch thick that extends to within 1 inch of the edge of the cloth. Sprinkle the oregano evenly over the salt.
Place the beef tenderloin on top of the salt at the far end of the cloth. It should run parallel to the center axis (and to your shoulders). Roll the cloth and salt around the tenderloin, starting in the far corner. The idea is to make a compact roll. Now take the points of cloth at each end of the resulting cylinder and tie them together on top of the tenderloin. Alternately, secure the roll with twine.The idea is to form a tight cylindrical packet. You should do this right before your charcoal or gas grill are ready.
Charcoal grill method: Light the coals in a chimney starter and rake them out into an even layer at the bottom of the grill. You will not need a grill grate. Lay the wrapped tenderloin right on the coals, knot side up. Grill for exactly 9 minutes. Using long handled tongs, gently turn the tenderloin package over and grill for exactly 8 minutes. Do not be alarmed if the cloth burns; it's meant to. In fact, the whole shebang should look about as appetizing as a fire-charred log.
Gas grill method: Preheat your grill as hot as it will go. There is no need to oil the grill grate. Arrange the cloth-wrapped tenderloin on the grate, knot side up. Grill until the bottom is charred black, about 9 minutes. (The grill should be covered.) Using long-handled tongs, urn the package over and grill until the other side is jet black, about 8 minutes.
Use an instant-read thermometer to test the tenderloin for doneness, inserting through the cloth and the salt into the center of the meat. When cooked to rare, the internal temperature will be about 125 degrees F; to medium-rare, 140 to 145 degrees F.
Transfer the charred tenderloin to a metal platter or rimmed sheet pan and let rest for 2 minutes. Lift the tenderloin with tongs and tap it hard with the back of a large, heavy chef's knife. The burnt shell should crack and come off. Using a pastry brush, brush any excess salt off the tenderloin. Transfer the tenderloin to a clean platter, cut it into 2 to 4 pieces and serve at once.