Leek and potato soup

Method

1. Melt the butter in a large lidded pan/casserole set over a medium heat. When the butter foams, add the leeks, onions and potatoes with plenty of salt and pepper, then cook gently, with the lid on, for 15-20 minutes. Stir every now and again to make sure the veg doesn’t catch on the bottom. Add the garlic and cook, stirring, for 1 minute.
2. Add the stock with the dijon mustard, bring to the boil, then turn down the heat to low and simmer for 15 minutes more until the veg are tender. Taste and season with salt and pepper. Serve half the soup spooned into warm bowls, sprinkled with the chives and freshly ground black pepper, with crusty bread to dip in. Freeze the rest of the soup.