This soup is delicious and warming. One chicken thigh, a few carrots, a couple of sticks of celery, a medium onion, and some lovely mushrooms - hey presto wonderful mushroom soup. You could use left over Christmas turkey instead of chicken. It's foolproof.
I kept the chicken from the stock for my next recipe, Mini stuffed peppers. So keep the veg and chicken to stuff the peppers. If you have your own favourite stock recipe, use that instead of mine. It needs to be a good strong one as mushrooms can be bland.