1. Set the oven to 180 degrees.
2. Peel the parsnips and remove the inner, tough core. Drizzle with rapeseed oil, sprinkle with salt, tumble in a couple of sprigs of thyme and roast in the oven for about 30 minutes until tender and just starting to take colour.
3. Meanwhile, chop the onion and sweat off in a little butter, keeping the temperature low so that it does not brown.
4. When the parsnips are cooked, remove and combine with the onions in a large saucepan, removing the thyme. Add the stock, most of the water and season, then bring to the boil and simmer for 10-15 minutes until the parsnips are completely soft.
5. Whizz using a stick blender or in a jug until smooth. Reserve or add the remaining water depending on the soup's consistency - use your common sense. Set aside until ready to serve.
6. Chop the mushrooms into slices, then set a medium frying pan onto a high heat. When the pan is nice and hot, add the mushrooms and leave for a minute or two until they start releasing some water. Add a generous bit of butter, season and continue cooking, stirring occasionally.
7. When the edges of the mushrooms start to crispen up, take them off the heat and dress with the leaves from a couple of sprigs of thyme
8. Position a quarter of the mushroom mix in the bottom of a soup bowl, then pour in the parsnip soup. Garnish with a sprig of fresh thyme and delight in the fact you have used up your Christmas leftovers!
Parsnip Soup with Chestnut Mushrooms
4 on a crisp, winter's day
324ml sachet Borough Broth chicken bone broth (this is life changing)
250g chesnut mushrooms
A little butter
Note: The quality of stock you use is so important and the Borough Broth company's is my absolute favourite - check their website out here: www.boroughbroth.co.uk also available on Ocado.