Braised chicken with porcini mushrooms

• 1 chicken
• 1 carrot
• 1 celery stalk
• 1

Cut the chicken into four pieces. If the breast is very big, cut it lengthwise into two or three parts. Separate the thigh from the drumstick.

Peel the carrot and slice into rounds. Remove any strings from the celery and chop. Slice the onion thinly.

Put half the butter and the oil in a pan with sides at least 12 centimetres high. Heat over low heat for 30 seconds then add the c