The classic beef wellington recipe is given an epic twist with parma ham, mushroom duxelle, caramelized onions, garlic and fresh horseradish. Take your favorite steak dinner and wrap it in beautiful pastry, perfect to make any night a celebration!
Pat filet mignon dry with paper towels and season generously with Kosher salt and black pepper.
On a cutting board, lay out a long piece of plastic wrap. It should be wider than the piece of beef and long enough to allow you to wrap it around the beef completely. If needed use two sheets overlapping.
In the middle of the wrap, layer prosciutto slices wider than the piece of beef. Be sure to overlap and shingle them so they don’t separate. Lay them vertically in front of you. Season with fresh ground pepper.
Spread mushroom duxelles in a thin even layer over the prosciutto using the back of a spoon.
Spread the caramelized onions over the duxelles in an even layer.
Place filet horizontally on top, in the center. Gently wrap the prosciutto around the beef using the plastic wrap to roll the mixture away from you. Wrap tightly and twist ends to get it cylinder tight. The tighter the beef is wrapped the better it will hold its shape and cook evenly.
Place the beef in the refrigerator for at least 15 minutes to firm up.
Lay out a clean, long piece of plastic wrap. It should be the same length as previously used so that it is long enough to allow you to wrap beef completely.
Dust board or countertop lightly with flour. Spread puff pastry on board and, using a rolling pin, roll it into a rectangle at least 4-inches wider than the beef roll on its shorter side. It should be large enough to wrap the beef, leaving some excess on the sides. You may need to put together two sheets. Use egg wash to bind the seams.
Remove the beef from the refrigerator. Remove the plastic wrap from the beef wrapped in prosciutto, and place on one end of the puff pastry.
In a bowl, beat egg and milk to create egg wash.
Brush puff pastry around beef roll with beaten egg wash. Carefully wrap beef in the puff pastry using the plastic wrap to pull tightly. The long ends of the sheet should meet and you can trim off any excess. Tuck or pinch the short ends closed so the beef is perfectly encassed. Use the plastic wrap to tightly seal the puff pastry. Return to the refrigerator for at least 5 minutes to firm up again or leave in overnight.
Adjust oven rack to center position and preheat oven to 425°F.
Place a sheet of aluminum foil on a baking sheet. Remove Wellington from refrigerator, remove the plastic wrap, and lay the Wellington seam-side down on the baking sheet.
Brush the top of the puff pastry with egg wash.
Using the back of a knife, score a leaf pattern into the pastry but be careful not to cut through the pastry. You can also cut out shapes with the leftover pastry and lay those on top to decorate. Brush with additional egg wash after you decorate.
Sprinkle liberally with coarse sea salt. I used Maldon.
Bake for approximately 25 to 30 minutes, or until pastry is golden brown and the internal temperature of the beef reaches 110º F for rare, 120º F for medium rare. The beef will continue to cook as it cools. Check at 30 minutes, if the beef is not at your desired temperature, leave in for longer but check it every few minutes. You do not want to overcook it. The use of a digital instant-read thermometer is very important.
Remove from the oven and let rest for at least 10-15 minutes before slicing.
If Wellington is browning too quickly and it has not achieved your desired temperature, cover it with a piece of foil to stop it from browning further.
To serve, Use a thin metal spatula to loosen Wellington from foil, then carefully transfer to a carving board. Slice off the ends with a sharp knife. Carve Wellington into thick slices, sprinkle cut surfaces with coarse salt, and serve.
Serve with your favorite side dishes.