You will need about two hours before serving: Preheat oven to 425 degrees. In a roasting pan with a roasting rack, place the tenderloin for roasting. Season with salt and pepper. Place in oven for about 40 minutes until the internal temperature is 120 degrees. Remove from oven, let stand for 30 minutes.

Do not turn off oven. Thaw pastry. Saute mushrooms and onions with seasoning until moisture is evaporated. Add red wine, remove from heat and add bread crumbs. The mushroom mixture should stick together slightly.

Roll out your puff pastry on a floured surface. Take cooled mushroom mixture and spread on puff dough. Place tenderloin on mushroom mixture. Wrap puff dough around the tenderloin and seal the bottom by pinching the two sides together. Roll over so seam is on the bottom, place on a cookie sheet. Brush with egg wash.

Bake for 10 minutes then reduce heat to 375 degrees. Bake another twenty minutes. Lift off sheet pan with two pancake turners to platter.

Serve with beef gravy, demi glaze or bordelaise sauce.