# What You'll Need:
→ Beef
01 - 2 lb beef tenderloin, trimmed
02 - Salt and freshly ground black pepper to taste
03 - 2 tablespoons vegetable oil
→ Mushroom Duxelles
04 - 1 lb cremini or button mushrooms, finely chopped
05 - 2 shallots, minced
06 - 2 cloves garlic, minced
07 - 2 tablespoons unsalted butter
08 - 2 tablespoons fresh thyme leaves, chopped
09 - Salt and pepper to taste
→ Assembly
10 - 10 slices prosciutto
11 - 2 tablespoons Dijon mustard
12 - 1 sheet puff pastry (14 ounces), thawed if frozen
13 - 1 large egg, beaten for egg wash
14 - Flour for dusting
# How To Make It:
01 - Preheat oven to 425°F.
02 - Season beef tenderloin with salt and pepper. Heat oil in heavy skillet over high heat. Sear beef on all sides for 2 minutes per side until browned. Remove and let cool completely.
03 - In the same skillet, melt butter over medium heat. Add shallots and garlic, sauté for 1 minute. Add mushrooms and thyme, season with salt and pepper, and cook until all moisture evaporates and mixture becomes paste-like, about 10 minutes. Let cool.
04 - Lay a large sheet of plastic wrap on work surface. Arrange prosciutto slices in slightly overlapping layer to form a rectangle just larger than the beef.
05 - Spread mushroom duxelles evenly over the prosciutto.
06 - Brush the cooled beef with Dijon mustard. Place beef on the duxelles-covered prosciutto.
07 - Using the plastic wrap, roll prosciutto and mushrooms around the beef into a tight log. Twist ends to seal and chill for 20 minutes.
08 - Roll out puff pastry on a floured surface to a rectangle large enough to fully encase the beef. Unwrap beef from plastic and place in the center of the pastry.
09 - Fold pastry over beef, trimming excess. Seal edges and place seam-side down on a parchment-lined baking sheet.
10 - Brush pastry with beaten egg. Decorate with pastry scraps if desired. Chill for 10 minutes.
11 - Bake for 40 to 45 minutes until pastry is golden and an instant-read thermometer inserted into beef reads 120°F for rare or 130°F for medium-rare.
12 - Let rest 10 to 15 minutes before slicing and serving.