Cook With M&S Chicken Gravy 350gCook With M&S Chicken Gravy. Made with chicken stock, onions and white pepper, this rich gravy is great for pouring over roast chicken and vegetables. Heat over the hob or in the microwave. Serves 4. Our Cook with M&S range includes 100s of time saving ingredients that make cooking dinner easy. Ingredients Chicken Stock (85%) (Water, Yeast Extract, Chicken Fat, Chicken Bones, Salt, Chicken, Carrots, Onions, Tomato Paste, Bay, Thyme), Onions,