Braided Challah

Directions

1. In a medium bowl, whisk the milk and yeast. Proof until the yeast bubbles and a thin layer of foam forms on the top, for about 10 minutes. Whisk in the psyllium powder and let it gel for 5 minutes.
2. In the bowl of a stand mixer fitted with the dough hook, combine the potato starch, sweet white rice flour, tapioca starch, brown rice flour, sugar, salt, xanthan gum (if using), and orange zest. Add the psyllium gel. Begin mixing on medium speed and add the olive oil and 3 of the eggs, one at a time. Mix the dough for 2 minutes, until it comes together and is lump-free. It will be sticky. Add a bit more milk if the dough feels dry.
3. Grease a large bowl with olive oil and scrape the dough into it, shaping the dough into a ball as much as possible. Turn it over to coat with oil. At this point, it won’t feel as sticky and you should be able to shape it more easily. Tightly cover the bowl with a clean kitchen towel or plastic wrap and refrigerate at least 4 hours or up to 12 hours. Chilling the dough is an important step, so don’t skip it. The dough needs to be very cold and hydrated to be braidable without the strands falling apart.
4. After the dough has chilled, lightly dust a work surface with tapioca starch and turn out the dough. If you are making a large challah, cut the dough into 3 or 4 equal pieces, depending on whether it will have 3 or 4 braids. If you are making 2 medium challahs, cut the dough in half, then cut each half into 3 or 4 equal pieces. Roll the dough pieces into balls, then into strands about 14 inches long (12 inches for medium challahs) and tapered at the ends. Arrange the dough strands vertically and pinch them together at the top. Braid each challah carefully and pinch again at the bottom. Tuck the ends under. Note that if your braid doesn’t turn out correctly the first time, you can knead the dough back together and start over.
5. Line a baking sheet with parchment paper. Put the challah on it, cover with a clean kitchen towel, and proof for 45 minutes to 1 hour, until nearly doubled.
6. Meanwhile, heat the oven 375°F. Lightly beat the remaining egg in a small bowl and brush the top and all the crevasses of the challah. Sprinkle the sesame seeds or sugar over the dough.
7. Bake for 35 minutes for a large challah or 30 minutes for medium ones, until golden brown. Let cool completely before cutting into it.
8. Do Ahead: The challah can be made 1 day ahead. Tightly wrap in parchment and store at room temperature, or freeze for up to 3 months.