2TbspFresh parsleychopped, plus sprigs for garnish (optional)
Preheat oven to 375°. In medium saucepan, bring 1 ½ cups water to a boil over high heat. Stir in quinoa and reduce heat to medium-low; cover and cook 8 minutes. Stir in lentils; cover and cook 7 minutes or until liquid is absorbed, and quinoa and lentils are tender. Spread on large plate; cool 10 minutes.
In large cast-iron or oven-safe skillet, heat 2 tablespoons oil over medium-high heat. Sprinkle pork with ½ teaspoon each salt and pepper; add to skillet and sear 5 minutes or until browned, turning to brown all sides. Transfer skillet to oven; roast pork 15-20 minutes or until internal temperature reaches 145°. Transfer pork to cutting board and tent loosely with aluminum foil; let stand 10 minutes.
In large bowl, whisk garlic, vinegar, mustard, and remaining 2 tablespoons oil and ¼ teaspoon each salt and pepper; stir in quinoa mixture, apple, cranberries, walnuts and parsley. Makes about 4 cups.
Cut tenderloin crosswise into ½" thick slices; serve over grain salad garnished with parsley sprigs, if desired.