Winter Leek Potato Soup

50g butter

450g potatoes, peeled and cut into 5mm dice

110g onion, peeled and cut into 5mm dice

450g white parts of the leeks, finely sliced (save the green tops for another soup or vegetable stock)

salt and freshly ground pepper

850ml – 1.2 litres light homemade chicken stock

125ml cream

125ml whole milk

To garnish

cream

finely chopped chives