Perfect blend: butternut soup with tahini and chestnuts.

A warming, wholesome, nutty and seedy soup for cold winter nights

Peel and halve 1kg of butternut squash and cut into large chunks. Put the squash into a large saucepan with 1 litre of vegetable stock and bring to the boil. Cover with a lid and leave to steam for 10 minutes until soft enough to crush.

Ladle the squash and its water into a blender and process until smooth and return to the pan.

Remove the leaves from 3 or 4 sprigs of rosemary and finely chop. You need enough to give a full tbsp. Toast 3 tbsp of sesame seeds in a dry, shallow pan over a moderate heat until golden then add 2 tbsp of olive oil and the rosemary. Crumble 8 cooked chestnuts (I used the canned variety) into the pan and cook for a minute or so until all is warm and deeply fragrant.

Bring the soup almost to the boil, checking the seasoning as you go, then ladle into soup bowls. Speckle the soup with a tablespoon of tahini to each bowl, then scatter some of the chestnut and sesame seed seasoning over the surface. Enough for 4.

The trick

Some people don’t peel butternut squash before using it in a soup. Much depends on the thickness of the skin and the age of the squash. If the skin is thin, then it is fine not to peel it. If you are using a pumpkin, remove the skin. It is important to process the soup in batches rather than all at once, when it is likely to overflow. A stick blender works a treat.

The twist

Use mushrooms instead of the chestnuts. I prefer small brown buttons, sliced in halves or quarters and cooked for a minute or two with the sesame oil and rosemary. A few drops of sesame oil, trickled into the soup as you serve, are worth a thought. I like to eat this soup with thick pieces of toasted sourdough bread, spread with cream cheese.

Email Nigel at nigel.slater@observer.co.uk or follow him on Twitter@NigelSlater