Classic Steak Wellington

1) Prep and sear the beef

1. If needed, trim off any silverskin. If one end is much thinner, tuck it under and tie with kitchen twine for a more even thickness.
2. Pat the tenderloin very dry. Season all over with kosher salt and pepper.
3. Heat a large skillet over medium-high heat. Add the oil. Sear the tenderloin until deeply browned, about 2 to 3 minutes per long side, then 30 to 60 seconds on each end.
4. Transfer to a plate. While it is still warm, brush all over with Dijon mustard. Let cool completely, then refrigerate while you make the duxelles.

2) Make the mushroom duxelles (dry is the goal)

1. Finely chop mushrooms in a food processor (pulse) or with a knife. You want tiny pieces, not puree.
2. In the same skillet over medium heat, melt butter with olive oil. Add shallots and cook 2 minutes, then add garlic and thyme for 30 seconds.
3. Add mushrooms and a pinch of salt. Cook, stirring often, until the mixture releases its liquid and then cooks dry, 12 to 18 minutes. It should look like a thick paste and you should hear more sizzling than bubbling.
4. If using wine, add it once the mushrooms start to dry, scrape up browned bits, and keep cooking until totally evaporated.
5. Taste and season with salt and pepper. Spread on a plate and cool completely. This matters. Warm duxelles turns into steam later, and steam is how pastry gets sad.

3) Wrap with prosciutto and duxelles

1. Lay a large sheet of plastic wrap on the counter. Overlap prosciutto slices into a rectangle large enough to wrap the beef.
2. Spread the cooled duxelles evenly over the prosciutto in a thin layer.
3. Place the chilled tenderloin along one edge and roll tightly using the plastic wrap to help you. Twist the ends like a candy wrapper to tighten the log.
4. Refrigerate at least 20 to 30 minutes (or up to 24 hours). This helps everything set and keeps the pastry stage low-drama.

4) Wrap in puff pastry

1. Heat oven to 425°F. Place a rimmed baking sheet in the oven to preheat (this helps crisp the bottom).
2. Lightly flour the counter. Roll puff pastry into a rectangle that can fully enclose the beef.
3. Unwrap the prosciutto-wrapped beef and place it seam-side down on the pastry. Brush pastry edges with a little egg wash to seal.
4. Wrap tightly, trim excess, and place seam-side down on parchment. If you want, use pastry scraps for simple decoration (keep it minimal so it bakes evenly).
5. Chill the pastry-wrapped Wellington 15 minutes if you have time.

5) Egg wash and bake

1. Whisk egg with water. Brush all over the pastry. Sprinkle with flaky salt if using.
2. Score the top lightly with a sharp knife (do not cut all the way through). Cut a few small vents on top.
3. Carefully transfer the parchment with the Wellington onto the preheated baking sheet. The pan is hot, so use oven mitts and pull the rack out a bit so you are not trying to land it blind.
4. Bake 25 to 35 minutes, rotating once, until deep golden brown. Start checking temp early. Insert the thermometer into the center of the thickest part and pull at 115°F to 122°F for medium-rare (carryover varies). For medium, pull at 123°F to 128°F.
5. Rest 10 to 15 minutes before slicing. This is not optional if you like juicy beef.

6) Optional quick pan sauce

1. While the Wellington rests, simmer beef broth and red wine in a small saucepan until reduced by about half.
2. Whisk in Dijon, then turn off heat and whisk in cold butter to gloss it up.

7) Slice and serve

1. Use a sharp serrated knife to slice into 1 to 1 1/2-inch pieces. Serve warm with the sauce if using.