3 1/2 lb Beef fillet, tied & larded 1 ts Water at room temp 1/2 c Sercial madeira
1 lg Egg yolk beaten with
3/4 lb Mushrooms, finely sliced 2 ts Arrowroot, dissolved in
1/2 lb Pate de foie gras, at room t 1/2 c Beef broth mp 2 tb Black truffles, finely chopp
Directions
Step #1 In a roasting pan, roast the beef in the middle of a preheated 400f oven for 25-30 mins or until a meat thermometer registers 120f.
Step #2 Let the fillet cool completely & discard the larding fat & strings.
Step #3 Skim the fat from the pan juices & reserve the juices.
Step #4 In a heavy skillet, stirring, cook the mushrooms in butter over mod-low heat, until all liquid they give off is evaporated & the mixture is dry.
Step #5 Spice up this with salt & pepper & let cool completely.
Step #6 Spread the fillet evenly with foie gras, covering the top & sides, & spread the mushrooms evenly over the foie gras.
Step #7 On a floured surface, roll one lb.
Step #8 of puff pastry into a rectangle about 20x12 inches, or large enough to enclose the roast completely.
Step #9 Invert the fillet in the middle of the pastry & fold up the long sides to enclose it, brushing the edges of the dough with some egg white to seal them.
Step #10 Fold the ends of the dough over the fillet & seal with the egg white.
Step #11 Transfer the fillet, seam side down, to a jelly-roll pan & brush the dough with egg wash.
Step #12 Roll out extra dough & cut out shapes with which to decorate the dough.
Step #13 After applying, brush with egg wash.
Step #14 Chill for at least 1 hr & up to 2 hrs.
Step #15 Bake the fillet in the middle of a preheated 400f oven for 30 mins.
Step #16 Reduce heat to 350f & bake an extra 5-10 mins more or until a meat thermometer registers 130f for medium rare meat & the pastry is cooked through.
Step #17 let this stand for 15 mins.
Step #18 In a saucepan, boil the reserved pan juices & the Madeira until the mixture is reduced by one fourth.
Step #19 Add the arrowroot mixture, broth, truffles, & salt & pepper to taste.
Step #20 Cook the sauce over moderate heat, stirring, for 5 mins or until thickened, being careful not to let it boil.
Step #21 Loosen the fillet from the pan, transfering it to a heated platter.
Step #22 Garnish with watercress.
Step #23 Serve the fillet cut into 3/4-inch thick slices, with the sauce.