Potatoes Gratin - Assemble Ahead?

[DCook]

I would like to attempt a potato gratin recipe tonight, and I was wondering if there was a way to assemble this ahead of time.

I've found a few recipes that call for par-boiling the potatoes first, and I'm wondering if that would be a good first step if one wanted to make this in advance

Tips? Thanks

[erin elizabeth]

When I've attempted to make things like a potato gratin ahead, I have pre-sliced the potatoes and held them in water, but I just saw a recommendation not to do that. The recipe I have in The Best Make-Ahead Recipe says to actually cook the gratin completely ahead of time, cool, cover, refrigerate, and then reheat in a 450 oven for 30 minutes.