A few people have posted under this recipe, asking for temperature and time when re-heating this brisket if made one day ahead....I'm wondering, too.
Thank you for asking here -- I wasn't aware of the questions on the recipe page but I'll go answer now!
I reheated a half recipe of this the other day, at 200 and it took about an hour to heat through. No harm in starting it early though, as long as you check it occasionally to make sure the liquid isn't evaporating away.
To clarify: I cooled and refrigerated the brisket, onions, and all their cooking juices in the pot I cooked it in, then the next day just scraped away a bit of the chilled fat on the surface and popped it back in the oven. I recommend this if possible.
Thanks, Kristen - I assumed that no one with Food52 had seen the questions posted under the recipe comments. I will be making the half-recipe as well and appreciate the clarification of your answer - will do as you suggest.