Its important that you use skimmed milk not whole milk. This is because you don’t want the sauce going into the freezer really thick. Otherwise it won’t be as nice when you defrost. Use skimmed which is rather watery and you will have a much better sauce.
Always go with your own judgement – if the sauce is too thick add more skimmed milk, if it is too thin add extra soft cheese. As you can see from the pictures at Christmas we get a huge soft cheese tub. Its perfect for cooking with over Christmas and a large one can often save you money overall.
I have put down serving size as 12. This is because it made enough for us for 3 separate meal servings. If you feel it needs it, season with salt and pepper.