Ingredients:
3 pounds center cut beef tenderloin
2 ounces pancetta, finely chopped 1/4 cup
2 tbl unsalted butter
12 ounces mushroom, mix of cremini, white, shiitake, oyster, finely chopped (4 cups)
1 shallot, diced
2 Tbl EVOO
2 garlic cloves, minced
2 Tbl thyme leaves
1 Tbl dry sherry
kosher salt and pepper
2 Tbl duck fat
10-12 slices prosciutto
1 egg
16 ounces puff pastry

Directions:
Using kitchen twine, tie the tenderloin into a 12-inch log, folding the thinner end onto itself.
Place pancetta in a cold 12-inch skillet and cook over medium heat until it starts to brown 6-8 minutes.
Add butter, raise heat to high, stir in mushrooms and shallot. Cook until the liquid released by the mushrooms has cooked off about 4-7 minutes. Reduce heat to medium and continue to cook until mushrooms are browned, stirring frequently, another 18-23 minutes. You want a deep golden color. Scrape bottom of pan as needed to prevent burning.
If the pan looks dry, drizzle olive oil, then stir in garlic and thyme leaves. Cook until fragrant about 2 minutes. Stir in sherry, scraping up the browned bits on the bottom of the pan. scrape mixture into a medium bowl to cool. Do not add salt yet.
in the same skillet, heat 2 tablespoons olive oil over medium high heat. season beef generously with salt and pepper, then sear on all sides until browned 1-2 minutes per side. transfer to a plate, and cool slightly. Remove any twine. Brush meat all over with mustard.
on a clean work surface, overlap long sheets of plastic wrap. place prosciutto slices on top to make about a 14x7in rectangle, arranging them in an even layer and overlapping the pieces slightly. spread cooled mushroom mixture on top.
Place beef along one long end of the prosciutto slices and roll prosciutto tightly around the beef. wrap tightly with plastic wrap. Twisting both ends like a candy wrapper, chilling in the fridge at least 30 minutes and up to overnight.
meanwhile, heat oven to 400F and line a rimmed baking sheet with parchment paper. In a small bowl whisk together egg and 1 tsp of water. Lay puff pastry out on the prepared baking sheet, lightly draping over the edges. The pastry needs to be at least 14 inches long and 13 inches wide to fully cover the beef; if it is not, roll it out.
carefully unwrap and place chilled log along the edge of one long side of puff pastry. Roll beef up tightly, then place it seam side down on the baking sheet. Tuck puff pastry over the ends of the beef to cover them, pinching to seal and folding underneath. Brush top and sides of pastry with egg wash, and use a small sharp knife to cut a few slits into the top of the pastry
Bake until the thermometer inserted into the center reads 115F for rare, 25-35 minutes. Remove from the oven and let rest for 10 minutes, then slice and serve while warm.
you’ll need a full pound of puff pastry to cover all the meat, so consider buying 2 packages to be able to provide full coverage.

Recipe taken from New York Times

Red Wine Sauce from Gordon Ramsay
Ingredients:
1 Table olive oil
2 ounces beef trimmings
3-4 shallots, sliced
6 black peppercorns
2 bay leaves
2 sprigs fresh thyme
1 Tablespoon red wine vinegar
600 ml red wine
600 ml beef stock

Directions:
1. Add olive oil to the pot. Add the beef trimmings and cook until browned.
2. Add the shallots, peppercorns, bay leaf and thyme sprigs.
3. Cook until the shallots are brown, about 5 minutes.
4. Add the dash of red wine vinegar and allow to bubble until it almost dries up.
5. Add the wine, let it boil until it’s about 3/4 reduced.
6. Add the stock, bring to the boil, then simmer for 40-60 minutes.
7. Remove the scum, strain the solids, season if needed.