Peel the potatoes and slice into 5 mm rounds.
Put the sliced potatoes into a frying pan with water. Boil for about 3 minutes and drain using a sieve (so the potatoes are only half-cooked)
In the frying pan (without water), add the milk and half-cooked potatoes. Add margarine and sprinkle a little salt, then simmer for about 5-6 minutes on a low to medium heat.
When the milk has reduced but there is still some liquid left, sprinkle with a little pepper, and it's done.
Transfer to a serving dish (I recommend using a spatula). I think it looks good with a little chopped parsley over the top.
I also tried adding some bacon in as well.