Sift flour and salt into processor bowl. Add half of the butter and process together for 10 seconds, until the mixture resembles fine breadcrumbs.

Add sufficient water to mix to a soft dough ball. Chill.

Place remaining butter between 2 sheets of greaseproof paper. Roll out a rectangle about 13 cm x 8 cm (5 x 3. inch)

On a lightly floured surface, roll out dough to a rectangle shape about 25 cm x 20 cm (10 x 8 inch.) Place rolled butter in the middle of the dough. Fold in the top and bottom thirds of the dough to enclose butter in parcel.

Give the dough a half turn so that the side seam is on your left, sealing edges well. Roll into a rectangle again and fold in top and bottom thirds of dough as before. Wrap and chill pastry for 15 minutes.

Repeat rolling, turning and folding pastry 4 more times, chilling between rollings.

Trim any fat from fillet, roll it into a neat shape.

Cut the garlic clove into slivers and insert them into the beef with the point of a sharp knife.

Spread the softened butter over the top of the fillet and cook meat for 10 minutes in a roasting tin in the oven set at 220°C (425°F) Gas no.7. Remove beef from oven and leave to cool.

Roll out the prepared puff pastry to an oblong 3 1/2 times the width of the fillet and 18 cm (7 inch) longer than the length.

Spread the PƒÂ¢tƒÂ© over the top of the fillet, place the meat, PƒÂ¢tƒÂ© side down in the centre of the pastry and sprinkle with thyme.

Fold the pastry over and under the meat, brushing the seams with water and sealing edges thoroughly.

Turn the pastry over so that the join is underneath. Prick the top with a fork and decorate with leaves cut from pastry trimmings. Chill.

Beat the egg with the oil and brush it over the pastry to glaze during cooking.

Stand the pastry roll on a wet baking tray and bake in the oven for 35 minutes on 220°C (425°F) Gas No.7. The pastry should then be golden brown.