Directions

1. Rinse pork tenderloins and pat dry. Working with one tenderloin at a time, place meat on a piece of waxed paper 6 inches longer than the meat. Rub 1/4 teaspoon onion powder evenly onto tenderloin then brush with about 1/4 cup sweet and sour stir-fry sauce. Sprinkle tenderloin with ground black pepper to taste. Wrap in waxed paper and refrigerate for at least 90 minutes for flavors to blend.
2. Preheat an outdoor grill to 350 degrees F. Spray grill rack with nonstick cooking spray. Grill tenderloins over indirect heat until pork reaches an internal temperature of 145 degrees F. (20-27 minutes), turning once or twice and brushing with remaining stir-fry sauce. Cover and let rest 5 minutes before serving.
3. Meanwhile, whisk together mayonnaise, Dijon mustard, 3 tablespoons stir-fry sauce and vegetable oil in a small bowl. Set aside.
4. Slice meat crosswise into medallions, about 1/2 - inch thick. Drizzle with Dijon sauce. Serve with rice.