If you want a more indulgent version, substitute some of the milk with cream.
You can also add some chopped tarragon into the soup. This will give an additional flavour of aniseed.
Here’s what you do:
Step 1 - Trim the leeks ensuring that you keep as much of the dark green part of the leek as possible. I think that the dark green bits bring a more rounded taste to the dish rather than a purely onion based taste. The green parts also give the soup a great colour.
Step 2 - Cut the leeks in half lengthways and then chop them all up. I like to have them in 1 cm semi circles so that they are bite sized and you don’t end up dribbling chunks of leek down your chin.
Step 3 - Wash the leeks thoroughly as there will be soil in between the layers.
Step 4 - Heat the oil and butter in the pot and when the butter has melted, add in the washed leeks.
Step 5 - The leeks need to be kept on a low heat so that they sweat down for at least 20 minutes. If it looks as though the leeks are sticking to the pot, add a little bit of water.
Step 6 - Add the stock and potatoes and bring to the boil. It should only take about 10 minutes for the potatoes to cook.
Step 7 - Add the milk and bring to the boil again. More milk can be added if required, but ensure that you don’t add too much or the leek flavour will be lost.
Step 8 - Season to taste. I add lots and lots of black pepper because I like the heat that it provides.
Step 9 - Liquidise the soup to your required consistency. I like to liquidise half so that you still get chunks of potato and ribbons of leek.
Step 10 - Serve with chunky bread like tiger bread.