Inspired by the book of Fredy Girardet: La cuisine spontanée, p230.
Comment: No cheese in the gratin dauphinois. The best way to prepare potatoes is to use a mandolin, set to 1.5 mm, but not everyone has one. It is then necessary to use dexterity and cut them with a knife into regular slices of 1.5 to 2 mm.
For the milk, if possible use whole milk and for the cream, use real cream.
As for the salt, use enough, however, 2 flat teaspoons should do the trick for 4 people.
1+ kg potatoes
6 dl milk
3 dl cream
2+ garlic cloves
Wash and peel the potatoes.
In a saucepan large enough to hold all the potatoes, and if possible non-stick, heat the milk, and half the cream. Salt, a little cayenne pepper and nutmeg. Chop or grate the garlic. Ensure that the mixture is fairly well seasoned as it will salt the potatoes.
Slice potatoes into thin slices (~2 mm). Add to the milk mixture and cook for 5 minutes, stirring gently.
Butter a gratin dish, pour in the potatoes and the cooking liquid. Add the remaining cream.
Place a few knobs of butter on top and put in the oven for 90 minutes at 160C (320F).