M&S Chicken & Mushroom Puff Pastry Pie Butter enriched shortcrust pastry filled with chicken and mushrooms in a cream sauce, topped with butter enriched puff pastry. Serve with carrot, swede and potato mash and peas. Serves 1. 100% of M&S Select Farms products meet our high quality and environmental protection standards. We know and trust all our Select Farmers, so you can trust M&S for your fresh food.