Melt the' butter in a large saucepan, add the onion and carrots, cover and cook for 4 - 5 minutes, until the onion is transparent. Stir in the flour and curry powder and cook, stirring, for 1 minute. Remove from the heat and gradually stir in the stock. Bring to the boil, stirring continuously, then simmer for 2 - 3 minutes, until thickened.

Reduce the heat, add the lemon juice and chicken and season to taste. Leave to cool.

When the chicken mixture is cool, roll out the pastry on a lightly floured surface to a 35.5 cm (14 inch) square. Using a sharp knife, cut into 4 squares.

Place the pastry on dampened baking sheets, then spoon the chicken mixture on to the pastry, leaving a border round the edges. Brush the edges of each square lightly with water. Fold each square in half and seal and crimp the edges to make a parcel.

Make 2 small slashes on the top of each parcel. Brush with beaten egg to glaze.

Bake at 220°C (425°F) mark 7 for 15-20 minutes or until the pastry is golden brown. Serve with a mixed salad or Brussels sprouts.