This is a great make ahead gravy recipe. Once made, let it cool completely before storing in an airtight container in the fridge and it will keep well for 3 days. It will thicken a little as it stands, so when you reheat it on the stovetop you may need to add a little stock or water. For longer storage, you can freeze the gravy, but it's best not to add the cream to it as this can become grainy when frozen and defrosted. Freeze for up to 6 months, thaw fully in the fridge before reheating and adding the cream.