All you need is a leek, butter, about 200ml double cream a little salt and plenty of black and white pepper
Slice the leek in half lengthways and wash thoroughly with cold water, making sure you get any dirt out that's hiding between the layers. Chop the halves up into 1cm width pieces. Put a knob of butter into a pan on a medium heat and add the sliced leeks when it's foaming. Fry for a good 8 minutes, ensuring you are softening but not colouring the leeks. Add the cream and stir as it heats through for about 2-3 minutes. Season with a pinch of salt and lots of black and white pepper. Serve as a side dish to lamb or chicken or simply enjoy with a jacket potato.
I had mine with one of those new McCains jacket potatoes that you just shove in the microwave. They're not amazing but it meant this creamy, deleicious, subtly oniony treat was ready in about 10 minutes. Lovely.