1

Preheat oven to 200°C or 180°C fan-forced. Heat oil in a large non-stick frying pan over high heat. Cook beef, turning, for 5–7 minutes or until browned. Transfer to a plate. Set aside to cool completely (see tip).

2

Reheat same pan over high heat. Cook onion, stirring, for 3 minutes or until softened. Add mushrooms and sherry and cook, stirring, for 7 minutes or until mushrooms are soft and liquid has evaporated. Season with salt and pepper. Set aside to cool completely.

3

Place pastry, slightly overlapping, on a large sheet of baking paper. Cut 4cm from each short end and join onto 1 long side to make pastry wider.

4

Spread mushroom mixture along centre of pastry (about the same length and width of beef fillet). Spread mustard over beef. Place beef on mushroom mixture. Fold pastry to enclose filling. Press edges to seal. Place Wellington, seam-side down, on paper.

5

Transfer beef on baking paper to a baking tray. Brush with egg. Bake for 50 minutes or until golden and cooked to your liking. Pour off cooking juices from tray. Loosely cover Wellington with foil and set aside to rest for 15 minutes before slicing thickly.

6

Meanwhile, boil, steam or microwave pumpkin until just tender. Drain. Process with sour cream and rosemary in a food processor until smooth. Season with salt and pepper. Serve Wellington with pumpkin puree.