Boulangere potatoes

1/ Pre-heat the oven at 392°F
2/ Heat 2 frying pans with 20 grams (2/3 oz) butter in each of them ; when the butter is 'meunière' (has become light brown but not burned), pour the potatoes into one of them and the onions into the other one
3/After 7 to 8 minutes, drain the potatoes, put 1/3 of them into an oven dish, add little table salt and pepper, cover them 1/2 of the onions, put 1 pinch of grated nutmeg on them, then cover with a second 1/3 of the potatoes, then with the remaining 1/2 of the onions then with the last 1/3 of potatoes (you have 5 layers in total)
4/Pour gently the stock so that it just comes to the top of the upper potatoe layer (not more)
5/Put the dish into the oven and let it cook during approximately 50 minutes (when cooked, no liquid must remain visible because it must have made a bond between potatoes and onions).

This easy recipe is very interesting because you can serve it with a roasted lamb leg or shoulder, saussages roasted into the oven, a nice thick veal chop pot roasted, etc...