first you'll need a potatoe slicer, otherwise, you'll spend forever thinly slicing potatoes for this dish.
next you'll need a good deep'ish glass bowl that is oven friendly to cook it in.
I generally heat up the oven at 150C degrees for this dish, although with experience you can choose your own setting.
slice potatoes and layer in dish, adding the odd peppercorn, again according to taste.
Cover them with 1 half double cream (works best) and 1 half Milk Add the salt into the mix.
then put in oven and leave for roughly 45mins-1hour.
When adding the milk/cream mix, just cover the potatoes, make sure that they're not floating too much, otherwise, it takes longer to cook.
This is the original French recipe, I learnt this when I was working in a restaurant in the South of France when I was 14years old.
Other people have been known to add a dash of Nutmeg, even an egg to the milk/cream mix and even add grated Cheese to to the top, but generally it all depends on taste.