1. Onion purée
Melt butter in a large, heavy-based pan over low heat. Add onions and a good pinch of salt. Cover with a lid and sweat very gently for 35–40 minutes, stirring occasionally, until completely soft and
translucent (do not allow onions to brown). Add the milk or cream and warm through. Transfer to a blender and blitz until completely smooth and silky. Pass through a fine sieve. Season with salt and white pepper. Refrigerate until service. Can be made up to 2 days ahead. Reheat gently before service.

2. Mushroom Duxelles
Melt butter in a large heavy-based pan over medium heat. Add the shallot and cook until soft, approximately 5 minutes. Stir in garlic and thyme and cook for a further minute. Add the mushrooms. Cook, stirring frequently, until the moisture has evaporated and the mushrooms are thick and jammy, approximately 15–20 minutes.
Add the fortified wine and cook until completely absorbed. Season generously with salt and black pepper. The duxelles should be dark and intensely flavoured, with just enough moisture to be glossy
and cohesive. Can be made up to 3 days ahead and refrigerated.

3. Red Wine Jus
Melt 15g butter in a heavy saucepan over medium heat. Add the shallot and garlic and sweat until completely softened, approximately 5 minutes. Stir in the thyme and red wine and reduce by half.
Add the beef stock and reduce by two thirds until the jus is glossy, 20–25 minutes. Strain through a fine sieve.
Just before service, bring back to a simmer and whisk in the remaining 30g cold diced butter. Season with salt.
Can be made up to 3 days ahead and refrigerated.

4. Pastry Shards
Preheat oven to 200°C fan-forced. Cut the pastry into elongated triangles or rectangles (one per portion plus a few extra). Place on a baking tray lined with baking paper. Place a second sheet of baking paper on top and weigh down with another baking tray - this keeps the pastry flat and even as it bakes. Bake for 12-15 minutes, until golden and crisp. Cool completely on a wire rack. Can be baked ahead. Store in an airtight container at room temperature for up to 12 hours, or freeze. Reheat from frozen at 200°C for 3-4 minutes.

5. Crisped Prosciutto
Preheat oven to 180°C fan-forced. Lay the prosciutto slices flat on a wire rack set over a baking tray. Bake for 8–10 minutes until completely crisp. Cool on the rack.
Handle carefully - the crisped prosciutto is very fragile. Can be made up to 3 hours ahead and kept at room temperature (do not refrigerate).

6. Tenderloin
Remove tenderloin from the fridge 45–60 minutes before cooking. Preheat oven to 180ºC. Tie tenderloin with butcher's twine at 3cm intervals to maintain an even cylindrical shape. Season generously on all sides with salt and cracked black pepper. Heat a heavy cast iron pan over high heat until smoking. Add the oil then sear tenderloin on all sides, including the ends, until a deep, golden crust forms, approximately 2–3 minutes per side. Reduce heat to medium and add the butter, garlic, thyme and rosemary. Baste continuously for 1 minute. Transfer to oven and roast for 15–20 minutes, for rare. Remove from the oven when the internal
temperature reaches 50°C. Rest on a wire rack for a minimum of 10 minutes before slicing. Tent loosely with foil if needed - the fillet will hold for up to 1 hour. Flash in a hot pan for 30 seconds per side before slicing, to revive the crust.

7. Plating
Remove the butcher's twine from the tenderloin. Using a sharp carving knife, slice the rested eye fillet into rounds approximately 4cm thick. Spoon a smooth disc of onion purée onto a warm plate. Place a spoonful of mushroom duxelles
neatly alongside. Arrange a slice of beef centrally on the plate, cut-side up to show the rare interior. Add the pastry shard and crisped prosciutto.

Finish with a drizzle of jus and garnish with micro herbs. Serve immediately.