Instructions

Season beef tenderloin generously with salt and pepper. Heat olive oil in a pan and sear beef on all sides until browned. Remove and brush with mustard. Let cool. In the same pan, sauté mushrooms, shallots, butter, and thyme over medium heat until moisture evaporates and mixture becomes a dry mushroom duxelles. Cool completely. Lay out plastic wrap, arrange prosciutto slices slightly overlapping, then spread mushroom duxelles evenly on top. Place beef on the mushroom-covered prosciutto and roll tightly using the plastic wrap. Chill for 15–20 minutes to set shape. Roll out puff pastry into a rectangle large enough to enclose the beef. Unwrap beef from plastic and place on pastry. Wrap tightly, sealing edges, and trim excess pastry. Brush pastry with egg yolk wash. Optionally score the pastry lightly with a knife for decoration. Chill again for 10 minutes. Bake in a preheated oven at 200°C (390°F) for 40–45 minutes, until pastry is golden brown and internal beef temperature reaches about 50°C (120°F) for medium-rare. Rest for 10 minutes before slicing thick portions and serving.