Poached Chicken

From an unidentified library book

This recipe came out of a book borrowed from the local library - title and author unknown (or rather, unremembered). It serves 4-6.

40 gms butter
1½ kg chicken pieces
1 small onion
700 mls milk
700 mls chicken stock
Bouquet garni (sprig of thyme, parsley and bay leaf - or sachets available from supermarket)
3 tablespoons cream/yogurt in a 50/50mix (or use all cream if yogurt is unavailable)

Cook the onion in butter until softened. Stir in the milk and boil for 5 minutes. Add the chicken, bouquet garni and enough stock to just cover the chicken. Reduce the heat to very low and cook until the chicken is tender (about 40 minutes) Remove the chicken from the pan and keep warm. Remove the bouquet garni from the sauce and boil until reduced to about 250 mls. Stir in the cream and yogurt, pour the sauce over the chicken and serve.