I don't know how you call in in the US...we call it Kartoffelgratin
Slice as much Potatoes as you like (not more as you can put into your gratin dish ).
For what you can see above the kids had 2.5kg Potatoes (we are five ).
Take 600ml sweet cream (whipped cream / fluid cream / whateveryoucallit cream) put in two eggs and 2-3 garlic toes (pressed).
Stir it...
Flavour the Potatoes with Oregano, Salt, black Pepper, Paprika powder (sweet or spicy...as you like ) and Curry powder.
Now spread the cream over the Potatoes and put it into the oven (has to be preheated to 170°C when using circulating air or 200°C with "normal" heat).
Leave it there for about 45min...check if the Potatoes are ready with a fork or a knive.
Actually it's meant to be a side dish to meat or at least with vegetables.
We have it as a principal meal with salad