Directions
<ol class="no-list-style"><li class="MethodStepper"><h4 class="step-title">Step 1</h4>Remove the beef fillet from the refrigerator at least 1 hour before cooking to allow it to come to room temperature. This ensures even cooking. Pat the beef dry with paper towels, then season generously with salt and pepper on all sides.</li><li class="MethodStepper"><h4 class="step-title">Step 2</h4>Heat a large frying pan over high heat until very hot. Add the olive oil and quickly sear the beef on all sides until browned but not cooked through, about 1-2 minutes per side. This crucial step creates a flavorful crust while keeping the inside rare. Transfer to a plate and, once slightly cooled, brush the entire fillet with Dijon mustard. Place in the refrigerator to cool completely.</li><li class="MethodStepper"><h4 class="step-title">Step 3</h4>For the duxelles, pulse the mushrooms, shallots, and garlic in a food processor until finely chopped but not puréed. Melt butter in a large frying pan over medium heat, then add the mushroom mixture. Cook, stirring frequently, for 15-20 minutes until all moisture has evaporated and you have a dry, dark mixture. This lengthy cooking process concentrates flavors and prevents a soggy pastry bottom. Add thyme and wine/stock, and continue cooking until liquid evaporates. Season with salt and pepper, then cool completely.</li><li class="MethodStepper"><h4 class="step-title">Step 4</h4>Lay a large piece of cling film on your work surface and arrange the prosciutto slices in an overlapping pattern, forming a rectangle large enough to wrap around the beef. Spread the cooled mushroom duxelles evenly over the prosciutto, leaving a 2cm border around the edges.</li><li class="MethodStepper"><h4 class="step-title">Step 5</h4>Place the cooled beef fillet in the center of the mushroom layer. Using the cling film to assist, carefully wrap the prosciutto and duxelles around the beef, creating a tight cylindrical package. Twist the ends of the cling film to secure, then refrigerate for at least 30 minutes to firm up. This chilling time helps maintain the shape during the next steps.</li><li class="MethodStepper"><h4 class="step-title">Step 6</h4>Preheat your oven to 200°C (fan 180°C). Roll out the puff pastry on a lightly floured surface to a rectangle approximately 3mm thick and large enough to wrap around the beef package with a 2cm overlap. Remove the cling film from the beef and place it in the center of the pastry.</li><li class="MethodStepper"><h4 class="step-title">Step 7</h4>Brush the edges of the pastry with beaten egg, then fold the pastry over the beef, sealing the edges carefully. Trim any excess pastry, but leave enough to tuck under for a neat finish. Place seam-side down on a parchment-lined baking tray. Refrigerate for 15 minutes to allow the pastry to firm up, which helps maintain its shape during baking.</li><li class="MethodStepper"><h4 class="step-title">Step 8</h4>Brush the entire pastry with beaten egg wash for a golden finish. Score the top of the pastry with a sharp knife in a decorative pattern if desired, being careful not to cut all the way through. Make a small hole in the top to allow steam to escape during cooking.</li><li class="MethodStepper"><h4 class="step-title">Step 9</h4>Bake in the preheated oven for 25-35 minutes until the pastry is golden brown and crisp. For medium-rare beef, the internal temperature should reach 54-57°C when tested with a meat thermometer. If the pastry browns too quickly, cover loosely with foil. Remember that the meat will continue cooking slightly during resting.</li><li class="MethodStepper"><h4 class="step-title">Step 10</h4>Remove from the oven and let rest on a wire rack for 10-15 minutes before slicing. This crucial resting period allows the juices to redistribute throughout the meat for maximum tenderness. While resting, prepare the sauce if using: reduce stock and wine in a saucepan until slightly thickened, then whisk in butter for richness.</li><li class="MethodStepper"><h4 class="step-title">Step 11</h4>Slice the Wellington into thick pieces using a sharp knife. The interior should reveal perfectly pink beef surrounded by the mushroom layer and crisp pastry exterior. Serve immediately with the red wine sauce if made, and your favorite side dishes like roasted potatoes, steamed asparagus, or glazed carrots.</li></ol>