Beef Wellington

Add the mushrooms, shallots, garlic and thyme to a food processor and pulse until finely minced.

Add the butter and olive oil to a large skillet, and heat until the butter foams. Add the mushroom mixture and sautée until nearly all the moisture has been driven off (8–10 minutes). Season with salt & pepper and set aside.

Tie the tenderloin with kitchen twine in several places to keep it from unraveling. Drizzle with olive oil and season with salt and pepper. Heat olive oil in a heavy-bottomed skillet until shimmering hot. Using tongs to hold the beef, sear it on all sides until evently browned. Set aside to cool.

Lay out about 24” of plastic wrap on the counter. Lay out the prosciutto in overlapping shingles to form a surface about 12” ⨉ 18”. Spread the mushroom mixture very gently over the prosciutto until it forms a thin, even layer. Sprinkle the thyme leaves over top.

Pre-heat the oven to 425°F on bake.

Remove the string from the beef, and coat lightly in mustard. Place it at one end of the proscuitto. While another person gently lifts the plastic wrap, wrap the proscuitto around the beef, taking care to tuck the ends around the sides of the roast. As your helper continues to pick up the plastic, roll the beef along the surface of the proscuitto, continuing to ensure it tucks neatly around the top and sides. When you're finished, you should have an unbroken layer of proscuitto completely covering the beef. Wrap tightly with plastic wrap, and place in the refrigerator for between 20–30 minutes to set.

Lightly cover a smooth, clean work surface with flour. Roll out your dough to create a ¼” thick layer. If using multiple sheets of dough, use a wet finger to dampen the seams to join them securely together. Use a rolling pin to lightly work the dough until it has become soft and pliant.

Mix the egg whites and water to make an egg wash. Unwrap the beef from the plastic wrap and place in the center of the dough. Flip the dough over the beef along the longer side so that it overlaps somewhat in the center. Brush the overlapping areas with egg wash to create a good seal. Flip the entire thing over so the seam is on the bottom. Trim the dough from the short ends so that it is just long enough to cover the height of the roast. Holding the top flap open, fold the button flap up against the roast. Brush it with egg wash, and then allow the top flap to fold closed against it, holding it in place. Repeat for the other side. Using a paring knife, cut small slits just through the dough layer at 3” intervals.

Cover a baking sheet with foil and grease lightly with olive oil. Place the roast in the center of the pan and brush with the remaining egg wash. Sprinkle coarse salt over the entire roast. cook in the oven until the pastry is golden brown, and the center of the roast has reach 125°F (about 40–45 minutes). Allow to rest for 10 minutes before cutting into thick slices and serving. Sprinkle with chives as a garnish.