Ingredients:
- 1 lb (450 g) Beef Tenderloin (centre cut, trimmed), cut into 1-inch (2.5 cm) cubes
- 1 Tbsp (15 ml) Olive Oil (high smoke point)
- 1 tsp Coarse Sea Salt and 1 tsp Freshly Ground Black Pepper, plus more to taste
- 2 Tbsp (30 g) Dijon Mustard
- 8 oz (225 g) Cremini Mushrooms, very finely diced or pulsed
- 1 Tbsp (15 g) Unsalted Butter
- 1 medium Shallot, finely diced
- 1 large Garlic clove, minced
- 1/2 tsp Fresh Thyme leaves
- 1 Tbsp (15 ml) Dry Sherry, Madeira, or good quality Red Wine (optional)
- 1 sheet (300 g) All-Butter Puff Pastry, thawed
- 1 Large Egg
- 1 tsp Water or Milk
- Flaky Sea Salt, for garnish
Instructions:
- Prepare the Duxelles: Melt butter in a small pan over medium heat. Add shallots and garlic; cook until fragrant (approx. 2 minutes).
- Add the finely diced mushrooms and thyme. Cook, stirring occasionally, for 8–10 minutes. Continue cooking until all moisture has evaporated and the mixture looks dark and paste-like. Deglaze with sherry/Madeira (if using) and cook until liquid is gone. Season well. Transfer duxelles to a cold plate and chill in the refrigerator for at least 15 minutes.
- Sear the Beef: Pat the beef cubes completely dry and season generously with salt and pepper. Heat olive oil in a heavy skillet until smoking hot. Sear the beef cubes quickly on all sides (about 30 seconds per side), aiming for a dark crust but leaving the center completely rare.
- Cool the beef immediately on a cooling rack. Once cooled, brush each piece thoroughly with Dijon mustard.
- Assemble: Preheat oven to 425°F (220°C). Roll the puff pastry sheet slightly thinner and cut into 12–16 squares (approx. 3.5 inches / 9 cm per side).
- Take the chilled duxelles and wrap a small amount around the sides of each mustard-coated beef cube, pressing gently to adhere.
- Place one duxelles-coated beef cube in the center of a pastry square. Bring the corners of the pastry up and pinch them tightly together at the top to seal the package, forming a neat parcel.
- Whisk the egg and water/milk for the egg wash. Brush the tops and sides of each bite generously. Sprinkle with flaky sea salt.
- Chill (Mandatory): Transfer the assembled bites to a parchment-lined baking sheet and chill them in the freezer for 15 minutes or the fridge for 30 minutes. This prevents shrinkage and maintains flakiness.
- Bake: Place the chilled Wellingtons immediately into the preheated oven. Bake for 18–20 minutes, or until the pastry is deeply golden brown and puffed and the beef is medium-rare.
- Rest: Remove from the oven and let them rest on the baking sheet for 5 minutes before serving warm.