🔥 Sear the beef: Season tenderloin with salt and pepper. Heat olive oil in a skillet and sear on all sides until browned (2-3 min per side). Let cool completely.
🍄 Make the mushroom duxelles: In a skillet, melt butter and sauté mushrooms, shallots, garlic, and thyme. Cook until liquid evaporates. Add wine and cook off any remaining moisture. Let cool.
🧻 Wrap the layers: Lay out plastic wrap. Arrange prosciutto in overlapping slices. Spread mushroom mixture on top. Place cooled beef in the center and roll tightly. Chill in fridge for 30 min.
🥐 Wrap in pastry: Roll out puff pastry. Unwrap beef and place in center. Wrap tightly, sealing the edges. Brush with egg wash. Chill again for 15 minutes.
🔥 Bake: Preheat oven to 400°F (200°C). Place wrapped Wellington on parchment-lined tray. Brush again with egg wash. Bake 35–40 minutes, or until golden brown and internal temp hits 125°F (for medium rare).
⏲️ Rest & slice: Let it rest for 10 minutes before slicing to maintain juices.