3 porcini crusted butter sauce Recipes

whole beef tenderloin , trimmed of fat, silverskin, and the chain (see cooks notes); or a 5- to 5 1/2-pound well-trimmed tenderloin roast, salt, freshly ground black pepper, olive oil, divided, dried porcini mushrooms, ground to a powder in a blender, black-truffle butter, softened, all-purpose flour, crimini (baby bella) mushrooms, trimmed and quartered into wedges, beef stock or low-sodium broth, divided, chopped scallion greens

dried porcini mushrooms (about 1 1/2 oz), divided, center-cut beef tenderloin, salt, divided, white pepper, divided, vegetable oil, boiling water, chilled butter or stick margarine, cut into small pieces