Grease a baking dish and lay the onions. Lay the chicken on top and add salt and pepper. Cover with foil and bake in the oven at 170ο C for 1 hour and 15 minutes. Remove the foil and allow the chicken to cool. Put the onions with their juices in a bowl.
Remove the bones from the chicken and cut up the meat. Put in the bowl containing the onions and add the parsley, cheese, milk and 4 beaten eggs. Lay half the pastry sheets in a baking dish, brushing each one with butter and then add the chicken filling.
Butter the remaining pastry sheets and cover the pie. Brush the sheet before last with the fifth egg so that it will brown nicely. Score the pie and cook for 45 minutes at 180° – 200° C.