• Season beef: Pat the filet mignon steaks very dry. Season all over with approximately 1½ teaspoons kosher salt and black pepper.
  1½ lb center-cut filet mignon, 2 tsp. kosher salt, 1 tsp. freshly cracked black pepper
  
• Sear the beef: Heat the avocado oil in a large skillet over medium-high heat until shimmering. Working in batches, sear the steaks for about 45-60 seconds per side, just until browned, briefly searing the edges as well. The centers should remain very rare since they will finish cooking in the oven.
  2 Tbsp. avocado oil
  
• Brush with Dijon mustard: Transfer to a plate and immediately brush each steak with Dijon mustard. Refrigerate until completely cool, approximately 20-30 minutes. Start Timer
  3 Tbsp. Dijon mustard
  
• Chop the mushrooms: Finely chop the mushrooms in a food processor using short pulses, or chop by hand. You want a fine, crumbly texture, not a purée.
  1½ lb cremini mushrooms
  
• Sauté: Melt the butter in a large skillet over medium-high heat. Add the shallots and cook for 2 minutes Start Timer, then add the mushrooms.
  3 Tbsp. unsalted butter, 2 medium shallots
  
• Cook: Cook for 15-18 minutes Start Timer, stirring frequently, until the mushrooms have released their moisture and the mixture becomes deeply browned and almost paste-like.
  
• Add the rest of the ingredients: Stir in the garlic, thyme, Worcestershire sauce, the remaining 1/2 teaspoon kosher salt, and a few grinds of black pepper. Cook for another 1-2 minutes Start Timer. It should be thick and spreadable, with no visible liquid remaining. Otherwise, the puff pastry can become soggy.
  4 garlic cloves, 2 tsp. fresh thyme leaves, 1 Tbsp. Worcestershire sauce, Black pepper
• Let cool: Spread the mushroom mixture on a plate or baking sheet and allow it to cool completely.
  
• Arrange prosciutto: Lay a large piece of plastic wrap on your work surface. Arrange 1 slice of prosciutto and spread approximately 2-3 tablespoons of the cooled mushroom mixture over the prosciutto, leaving a small border.
  8-9 oz. thin slices of prosciutto
  
• Wrap the beef in prosciutto: Place one chilled filet piece in the center. Using the plastic wrap to help you, fold the prosciutto and mushrooms snugly around the beef, covering it as completely as possible.
  
• Wrap in plastic: Twist the plastic wrap tightly around the bundle to help it hold its shape. Repeat with the remaining fillets. Refrigerate for 20-30 minutes to firm up. Start Timer
• Roll out puff pastry: On a lightly floured surface, roll each puff pastry sheet just enough to smooth the seams. Cut each sheet into rectangles. You'll use one rectangle per Wellington.
  2 packages frozen puff pastry
  
• Make the egg wash: Whisk the egg and water together in a small bowl.
• Wrap: Remove a beef bundle from the plastic wrap and place it in the center of a pastry rectangle. You can brush the edges of the puff pastry with egg wash to help seal as you go. Fold the pastry around the beef, trimming any excess pastry as needed. Press the seams together firmly.
  
• Repeat and chill: Place seam-side down on a parchment-lined baking sheet or a plate and keep chilled while you roll the rest. Repeat with the remaining Wellingtons, dividing them between two baking sheets or plates (Whatever can fit in your fridge). Chill the assembled Wellingtons for at least 20 minutes before baking. Start Timer
  
• Preheat & brush egg wash: Preheat the oven to 425°F. Brush the tops and sides of each Wellington with the egg wash.
  1 large egg, 1 Tbsp. water
• Score: Using a sharp knife, lightly score a decorative pattern into the pastry, being careful not to cut all the way through. Sprinkle the tops with a tiny pinch of maldon flaky sea salt.
  Flaky sea salt
• Bake: Bake for approximately 20-25 minutes Start Timer, rotating the baking sheets halfway through, until the pastry is deeply golden and crisp. (while they bake I would start the sauce recipe below).
  
Start checking the internal temperature around 15-18 minutes. For medium-rare beef, aim for approximately 125-130°F after resting. Remove the Wellingtons a few degrees before your target temperature to account for carryover cooking.
• Rest and serve: Allow the Wellingtons to rest for 8-10 minutes before serving Start Timer. Garnish with fresh thyme, if desired and serve with the peppercorn sauce on the side (recipe below). Serve whole for a dramatic individual presentation, or slice in half to reveal the beautiful layers.
  Fresh thyme
  

Make the peppercorn sauce

• Sauté the shallot: Melt butter in a medium skillet over medium heat. Add shallot and cook for 2-3 minutes until softened and fragrant, without browning. Start Timer
  1 Tbsp. unsalted butter, 1 small shallot
  
• Deglaze with cognac: Remove the skillet briefly from the heat, add the cognac, then return to the heat. Simmer for 2-3 minutes, scraping up any browned bits, until reduced by about half. Start Timer
  1/3 cup brandy or cognac
  
• Reduce the broth: Add beef broth and thyme, if using. Bring to a simmer and cook for 3-5 minutes Start Timer, until reduced by approximately half.
  3/4 cup low-sodium beef broth, 1 small sprig fresh thyme
  
• Finish the sauce: Reduce heat to medium-low. Stir in heavy cream, crushed peppercorns, and Dijon mustard. Simmer gently for 3-5 minutes Start Timer, stirring occasionally, until the sauce thickens slightly and coats the back of a spoon. It could take longer to thicken, up to 10 ish minutes. If it's not thickening you can stir 1 tsp cornstarch into 1 Tbsp cold water, whisk it into the simmering sauce, and cook 1 minute.
  1/2 cup heavy cream, 2 tsp. coarsely crushed black peppercorns, 1 tsp. Dijon mustard
  
• Season and serve: Remove thyme. Taste and adjust with salt or additional peppercorns. Serve warm alongside sliced Beef Wellington (not on top, but on the side of the bites). How amazing is this?! Enjoy!!!
  Kosher salt