In the pan you've cooked the meat add the sliced mushrooms ( I used chestnut mushrooms )

Fry them for about 5 minutes

Add the cream stir through

Now add the mustard and mix well

Season and serve over the meat

If ( like me ) you don't like mushrooms , fry some onions until soft , add in some cooked apple and chopped sage , stir through some cream and season . Cook for a minute or 2 and serve