1. Boil the chicken in a large pan with a bouquet garni and just enough water to cover.
2. When tender, remove the chicken from the pan, drain and cool it, reserving the stock.
3. Scald the grapes in a little boiling water, remove the skins, halve them and remove the pips.
4. Arrange the chicken and the grapes in a fairly deep pie dish - about 5 cm (2 in).
5. Season with salt, pepper and a little nutmeg.
6. Pour in enough stock to come just to the top of the chicken, without covering it, about 300 ml (1/2 pint).
7. Dot with butter. Roll out the pastry and put on the lid.
8. Glaze with beaten egg and bake at 220°C, 425°F, mark 7 for 30 - 35 minutes until the pastry is brown and puffed.
9. When the pie is done, carefully cut a circle from the lid, squeeze in the orange juice, cut the pastry circle into wedges and arrange in the hole.
10. Serve hot.