Ingredients:

  • 4 x 175g (6 oz) Beef Fillet Mignon Steaks (center-cut, 3-4 cm / 1.5 in thick)
  • 1 tbsp (15 ml) Olive Oil, plus extra for searing
  • 1 tbsp (15 g) Unsalted Butter
  • Coarse Sea Salt and Freshly Ground Black Pepper, to taste
  • 3 tbsp (45 ml) Dijon Mustard
  • 400 g (14 oz) Mixed Mushrooms (e.g., Cremini and Shiitake, roughly chopped)
  • 2 large Shallots, finely minced
  • 2 cloves Garlic, minced
  • 1 tbsp (15 g) Unsalted Butter (for duxelles)
  • 1 sprig Fresh Thyme, leaves only
  • 2 tbsp (30 ml) Dry Sherry or Madeira
  • 8 slices Prosciutto (thinly sliced, high quality)
  • 500 g (1 lb 1 oz) All-Butter Puff Pastry, chilled
  • 1 large Egg Yolk, beaten with 1 tsp (5 ml) water (for egg wash)
  • A pinch of Flaky Sea Salt (for finishing)

Instructions:

  1. Pulse the mushrooms, shallots, and garlic in a food processor until they form a coarse paste. Melt butter in a skillet over medium-high heat. Add the mushroom paste and thyme leaves. Cook, stirring constantly, for 10–12 minutes until all moisture has completely evaporated. Add the Sherry/Madeira and cook for 1 minute until absorbed. Season well. Spread thinly and refrigerate for 20 minutes until completely cold.
  2. Generously season the beef fillets with salt and pepper. Heat oil and butter in the skillet over high heat. Sear each fillet for 30–45 seconds per side, creating a deep brown crust (interior must remain raw). Remove the steaks, set them on a wire rack to rest for 10 minutes. Brush all sides of the cooled fillets with Dijon mustard.
  3. Lay two sheets of cling film on your workspace. Arrange two slices of prosciutto on the film, overlapping, to form a blanket for one steak. Spread an even layer of the chilled duxelles over the prosciutto blanket. Place one mustard-coated fillet at the edge. Use the cling film to tightly roll the beef, prosciutto, and duxelles mixture into a compact cylindrical parcel. Twist the ends of the cling film to seal and refrigerate the four beef parcels for a minimum of 30 minutes.
  4. Roll the chilled puff pastry to a thickness of about 3 mm (1/8 inch). Cut the pastry into four equal squares. Remove a chilled beef parcel from the cling film and place it diagonally on a pastry square. Brush the edges with egg wash. Fold the corners up to meet in the center, sealing the pastry tightly around the beef. Place the Wellingtons seam-side down on a prepared baking sheet, brush generously with egg wash, and score the tops lightly. Refrigerate the Wellingtons for a final 30–45 minutes.
  5. Preheat oven to 200°C (400°F). Bake the Wellingtons for 20–25 minutes until deeply golden brown. Crucially, insert a probe thermometer into the center of one Wellington: target 54°C (130°F) for Medium-Rare. Once the desired temperature is reached, remove from the oven and let the Wellingtons rest for 8–10 minutes before serving.