Fillet of beef en croute a la bisontine with sauce bearnaise, from the Roux Scholarship 2010

This recipe, a classic from the Escoffier era, was the dish chosen for the finals of the Roux Scholarship 2010, which was won by BaxterStorey chef Kenneth Culhane. For more about this year's competition, see Star of the show - the 2010 Roux Scholarship final.

INGREDIENTS
(Serves four)

• 1kg rough puff pastry
• 1 fillet of beef (about 800g-1kg), cut from the thicker end
• Salt and freshly ground pepper
• 80g clarified butter
• 80g butter
• 1kg button mushrooms, finely chopped
• 2tbs chopped parsley
• Juice of 1 lemon
• 60g shallot, finely chopped
• 100ml double cream
• 12 large spinach leaves
• 4 herb crêpes about 26cm diameter
• Egg wash

METHOD

Trim the fillet of any membrane, then season all over with salt and pepper. Heat the clarified butter in a roasting pan over a medium-high heat and sear the beef for three to four minutes until golden, turning to colour evenly.

Transfer to the oven and roast for eight minutes, turning the meat over after four minutes. Lift the beef on to a wire rack and leave to cool completely. At this stage, it will be very rare.

For the mushroom duxelle, heat the 80g butter in a pan over a medium heat. Add the mushrooms and lemon juice and cook, stirring from time to time, until all the moisture has evaporated. Add the shallot and cook for another two minutes, then pour in the cream and cook, stirring until it is all absorbed. Add the chopped parsley and season to taste and set aside to cool, then chill.

Blanch the spinach leaves in boiling salted water for 30 seconds, then drain and refresh in cold water. Drain well, separate the leaves and pat each one dry with kitchen paper.

To assemble, roll out the pastry on a lightly floured surface to make a 40cm x 25cm rectangle, 3-4mm thick. Trim the sides to neaten. Place two crêpes along the middle of the rectangle and cover them with eight spinach leaves. Spoon and spread a 1cm thick band of mushrooms duxelle along the middle of the spinach crêpes. Put the cold beef fillet on top and thickly cover the whole surface, including the ends, with the remaining duxelle.

Cover the mushroom duxelle with the remaining spinach leaves and crêpes. Fold the crêpes over the beef and if necessary cut off any overlapping parts with scissors.

Lightly brush the two ends of the pastry rectangle with egg wash. Fold one side over the beef, brush it and the ends with egg wash, then fold to the side over the beef.

Roll out the two ends of the pastry to a 4-5mm thickness, and trim to an 8cm length. Brush these with egg wash and fold them over the beef. Turn the pastry-wrapped beef over on to a baking sheet, egg wash the entire surface of the pastry and refrigerate for 10 minutes.

Meanwhile, heat the oven to 200°C/Gas 6. Brush the entire surface of the pastry with egg wash a second time and score it with leaf patterns using a knife tip. Cut a small aperture in the middle of the pastry to allow the steam to escape during cooking. Bake for 25 minutes if you like your beef rare, or 35 minutes for medium. If the pastry becomes too brown as it cooks, cover loosely with foil and lower the oven setting to 170°C/Gas 3.

Use a palette knife to transfer the cooked beef en croûte to a wire rack and leave it to rest for five minutes. Carve three thick slices of the beef en croûte and transfer the fillet on to a serving platter. Disregard the first slice with the crust, arrange the second slice on a plate and the third in front of the beef on the platter.

For the garnish à la Bisontine (Escoffier)

Place four croustades made from pommes duchesse filled with creamed purée of cauliflower on the platter and one croustade on the plate. Place four braised Gem lettuce on the platter and one on the plate.

Arrange watercress for presentation and serve the béarnaise sauce separately.