I still used a metal pan, just to see if the culprit was the cream itself.
As I suspected, it was the light cream all along. It wasn't the metal pan. The only mistake was that I didn't use full cream. But this time, I used full cream and the result was very good. I did use too much sauce this time, next time add as much milk/cream mixture to the level that you don't cover the potatoes entirely.
This might look gross, but it is very tasty. The sauce hasn't separated, but is very thick and creamy.
|The thick sauce is bound together|
Unlike the first time, where the sauce separated.
|You can see that the sauce is shifted into water and fat particles|
Go here to learn how to make Gratin Dauphinois.