1Season beef with salt and pepper. Place the oil in a saucepan and sear the meat on all sides. Remove and let cool. Brush the meat with mustard
2Place the mushrooms in a food processor and puree. Add the salt,pepper, onion powder, and garlic powder. Cook in a dry pan until all moisture has evaporated.
3Lay out the prosciutto on a piece of cling wrap each slightly overlapping the other. Spread the mushroom mixture over the prosciutto. Place beef in the middle and roll the prosciutto and mushroom mixture over the beef. Roll tight with the cling wrap and twist the ends closed. Place in refrigerator for 15 minutes
4Roll out the pastry big enough to cover the meat. Place the meat in the center of the pastry. egg wash the ends and place the meat in the middle. Fold each side over the meat then enclose the sides. Cut off any extra pastry. Egg wash the entire thing. Score the outside for venting
5Place parchment paper on baking sheet and oil it. Place meat seam side down on baking sheet and bake at 400 degrees for about 40 minutes internal temp 130 degrees. Let rest for 10 minutes before cutting
6Meanwhile make the sauce.
In a saucepan bring the wine shallots and thyme to a boil and reduce to about 1/3 cup. Add the beef broth and vinegar. Cook until slightly thickened. Taste and season with salt and pepper. Stir in the butter and remove from heat. Serve over the wellington.