Beef Tenderloin with Mushroom Sauce

MAKES 8 TO 10 SERVINGS 3 tablespoons olive oil 1 (5-pound) beef tenderloin, trimmed 1 tablespoon garlic powder 1 1/2 teaspoons salt 1 teaspoon ground black pepper Mushroom Sauce (recipe follows) Garnish: chopped fresh thyme 1. Preheat oven to 350°. Line a rimmed baking sheet with aluminum foil. 2. Rub olive oil on outside of…