Trim the top 3cm and the roots off the leeks. Halve them and rinse out any grit. Finely slice them. Warm a pan for 1 min, then add ½ tbsp oil and the leeks. Season with a pinch of salt and pepper. Cover. Turn the heat down to low and sweat for 10 mins till the leeks are soft. Stir now and then.

While the leeks sweat, trim the ends off the celery stick and finely slice it. Peel the potatoes and chop them into chunks around 1cm wide. Peel and crush or grate the garlic.

Stir the celery, potatoes and garlic into the leeks. Crumble in the stock cube and pour in 700ml boiling water. Add the bay leaf. Cover, turn the heat up and bring to the boil. Lower the heat and simmer for 15 mins till the veg are tender.

Meanwhile, tip the cashews into a dry frying pan. Toast over a medium heat for 2-3 mins till golden, shaking the pan. Roughly chop the toasted nuts, then stir half into the soup. Fish out the bay leaf.

Taste the soup. Add more salt and pepper if it needs it. You can leave the soup chunky or blitz it in a blender, or with a hand-held blender, till smooth and velvety. Ladle the soup into warm bowls and top with the remaining toasted cashews to serve.