Hey Jules. Thanks for this. Interesting news for me! And I just found a useful reference:
https://cookswithoutborders.com/new-story/tag/best+no-cheese+gratin+dauphinois

I want to try GD sometime without the cheese, but I dunno, the gruyere is a tough partner to nix.

I’m glad to see that Elizabeth David, in the link above, does note that several French cooking masters included cheese.