Recipe from The Bread Bible by Rose Levy Beranbaum
Notes: I've made this loaf two weeks in a row now for Friday dinner, as Flick and I have hosted a record-setting four Shabbats in a row with friends. It is a far superior challah to another pareve recipe I made recently. This recipe uses a sponge starter with lots of eggs, and oil and honey to ensure tenderness.
One thing about this recipe (and the book in general) is that the headings in the instructions are sometimes misleading. You have to read it quite closely to figure out what's going on. Make sure to read the errata as well.
The second time I made this, I made the sponge on Thursday morning, covering it with the flour blanket. It sat in the fridge all day, then I kneaded the dough and let it rise in the fridge overnight. On Friday morning, it hadn't risen that much. I braided a four-strand loaf, and let Dr. S egg-wash and bake it. This is quite a delicious loaf that keeps for a few days.