Boeuf en Croûte — Beef Wellington

Ingredients

• 1.2 kg beef fillet, centre-cut, trimmed, tied if necessary to maintain shape
• 400 g mushrooms, processed to fine duxelles and cooked until bone-dry
• 8–10 slices Parma ham, laid overlapping on cling film
• 500 g all-butter puff pastry, rolled to 3 mm thickness
• 2 eggs, beaten, for egg wash
• Optional
• 60 g mousse de foie gras, spread in a thin, even layer over the duxelles
• to taste flaky sea salt and black pepper, for seasoning the fillet

Method

1. 1
   Season the trimmed fillet generously on all surfaces. Heat a heavy pan until blazing hot and sear the fillet on every surface — 30 to 45 seconds per side — until a deep, uniform colour is achieved. Remove and cool completely before any further preparation; a warm fillet will melt the butter in the pastry and compromise the bake.
2. 2
   Cook the mushroom duxelles over high heat, stirring frequently, until every trace of moisture has evaporated and the mixture is dense and dark. Press the duxelles against the pan: no liquid should weep from it. This is where the dish lives or dies — any residual moisture will generate steam during baking and render the pastry irreparably soggy.
3. 3
   Lay the Parma ham slices on a sheet of cling film, overlapping slightly to form a rectangle with no gaps. Spread the dry duxelles evenly over the ham; if using foie gras mousse, spread a thin layer over the duxelles first. Place the cooled fillet at one edge and roll tightly using the cling film to form a firm, uniform cylinder. Twist the ends to secure and refrigerate for 30 minutes. The parcel should hold its shape without slumping when unwrapped.
4. 4
   Roll the puff pastry to 3 mm thickness — no thicker, or the pastry will require more oven time than the beef can withstand. Unwrap the chilled fillet parcel, place it on the pastry, and fold the pastry around it, sealing the seam with egg wash and pressing firmly to close. Decorate the surface with pastry trimmings if desired. Brush the exterior generously with egg wash, then chill the wrapped fillet for a further 20 minutes; cold pastry rises more decisively in the oven.
5. 5
   Apply a second coat of egg wash immediately before baking. Place in an oven preheated to 220 °C and bake for 20 to 25 minutes. The pastry is ready when it is deeply golden and shatters audibly when tapped with a fingernail.
6. 6
   Insert a probe thermometer through the end of the parcel into the centre of the fillet. The target reading is 48–50 °C for medium-rare; the internal temperature will rise a further 3–5 degrees during resting. Remove from the oven and rest for 10 minutes without cutting. Slice with a sharp serrated knife into thick rounds: each cross-section should show a flaky golden shell, a thin dark layer of duxelles, and an unbroken pink centre.