Make an impressive main course with this step-by-step guide to traditional Beef Wellington, featuring tender beef tenderloin wrapped in savory mushroom duxelles and crisp puff pastry.
Season the beef tenderloin generously with salt and pepper. Sear the beef in hot olive oil in a skillet on all sides until deeply browned. Remove from heat and brush all over with Dijon mustard. Let cool completely.
Prepare the duxelles: In the same skillet, melt the butter over medium heat. Add the chopped mushrooms and shallots. Cook, stirring often, until all the moisture has evaporated and the mixture is dark and dry, about 15-20 minutes.
Stir in the thyme leaves and sherry. Cook until the liquid evaporates again. Season with salt and pepper. Spread the duxelles onto a plate to cool completely.
Lay out a large piece of plastic wrap. Arrange the prosciutto slices in an overlapping rectangle large enough to wrap the entire tenderloin.
Spread the cooled mushroom duxelles evenly over the prosciutto layer.
Place the cooled, mustard-coated beef tenderloin at one end of the prosciutto. Use the plastic wrap to tightly roll the prosciutto and duxelles around the beef, forming a compact log. Twist the ends of the plastic wrap to secure the shape. Refrigerate for at least 30 minutes to firm up.
Lightly dust a clean surface with flour. Roll out the puff pastry into a rectangle large enough to fully enclose the beef log.
Remove the beef from the plastic wrap and place it on the pastry. Brush the edges of the pastry with the beaten egg wash.
Wrap the pastry tightly around the beef, trimming any excess dough. Seal the seams well. Place the Wellington seam-side down on a baking sheet lined with parchment paper. Brush the entire surface with egg wash. Chill for another 15 minutes.
Preheat your oven to 400 degrees F (200 degrees C).
Score the top of the pastry lightly with a sharp knife in a decorative pattern, being careful not to cut all the way through. Brush with a second coat of egg wash.
Bake for 30 to 40 minutes, or until the pastry is golden brown and crisp, and an internal thermometer reads 125 degrees F (52 degrees C) for rare or 135 degrees F (57 degrees C) for medium-rare.
Let the Beef Wellington rest on a cutting board for at least 10 minutes before slicing into thick portions.
Notes
For the best results, ensure the duxelles is completely dry before spreading it onto the prosciutto. Excess moisture will make the pastry soggy.
Use a high-quality beef tenderloin for this recipe; the flavor depends on the quality of the meat.
If you prefer a deeper color, you can chill the wrapped Wellington for up to 24 hours before baking.