Cut the chicken into 6 pieces. Melt the butter and oil in the open pan. Lightly fry the chicken but do not allow to brown. Add water, salt and pepper. Close the lid and bring to pressure. Cook for 15 minutes. Release steam quickly. Lift the chicken out of the pan, drain and place on a warmed dish. Use the cooking liquid as stock. Beat the eggs and mix in the cream. Pour the mixture into the cooker. Over low heat, stir the sauce until it becomes smooth then remove from the heat immediately. Be careful not to boil the sauce. Cover the chicken with the sauce.