1. Preheat oven to 450°F.

2. Mix together the ancho, cumin, paprika, coriander, garlic powder, 2 teaspoons salt, and 1/2 teaspoon pepper. Rub 1 tablespoon of the oil on the tenderloin, then rub evenly with the spice mixture. Let stand at room temperature for 30 minutes.

3. Heat the remaining tablespoon a large skillet over medium-high heat. Sear the tenderloin (bending it to fit in the pan if necessary) until golden brown on all sides, about 3 minutes per side. Transfer the tenderloin to a rimmed baking pan and roast until an instant-read thermometer inserted into the center of the tenderloin reads 130°F (for medium-rare), about 20 minutes. Transfer to a cutting board and let rest for 10 minutes. Remove the string and slice crosswise.