From: The New Jewish Holiday Cookbook
4 cups bread flour
2 to 3 cups unbleached flour, divided
2 packets (4 1/2 tsp) fast-acting dry yeast
1/3 cup sugar
2 tsp salt
4 large eggs, divided, or 8oz egg substitute
1/3 cup canola oil
1 1/2 cups hot water (120 to 130 degrees- no hotter)
approx 1 tsp poppy or sesame seeds, optional
In the large bowl (5 qt or larger) bowl of a heavy-duty electric mixer (ie, KitchenAid or similar) with a dough hook, put the bread flour, 1 cup of the unbleached flour, yeast, sugar, and salt. Mix the dry ingredients by holding the hook in your hand and using it to stir. Measure out 3/4 cup of the egg substitute, or use 3 eggs, lightly beaten. Add the 3 eggs (or egg sub) and oil to the flour mixture and stir in with the hook. It is not necessary to mix well at this point. Finally, add the hot water to the bowl and stir in.
Set the bowl into the mixer and attach the dough book. Turn the mixer to kneading speed. As the dough kneads, lightly sprinkle just enough unbleached flour around the inside surface of the bowl so that the dough stays on the hook and does not come down off the hook into the bottom of the bowl. You will probably need to use more flour in the beginning, and less as the dough kneads. Let the dough knead for about 5 to 10 min, or until it is very smooth. When it is almost done kneading, it should need very little or no more flour and should almost clean the inner surface of the bowl. Note: If the dough rises over the top of the hook, scrape it down and add more flour. This may happen if the bowl is smaller than 5 qts. In the future, consider reducing the recipe by one-third and making smaller loaves.
Remove the dough hooks from the dough, but leave the dough in the mixer bowl. Cover the bowl with a plastic lid or a piece of plastic wrap so the dough does not dry out and let it rest for about 15 to 30 min. This is not a rising period, but time to let the gluten ease so the dough can be shaped. If the room is warm, the dough may rise slightly.
To easily remove the dough from the bowl, sprinkle some flour over the dough, and use a spatula to push the flour all the way down the sides of the bowl while completely loosening the dough at the same time. Turn out the dough onto a lightly floured board, and press it gently into a large rectangle (about 10x14 inches) of even thickness. For two 4-braid large challot, use a knife or sharp-edged dough-scraper to cut the dough in half; then cut each half in half again to make four; then cut each piece in half once more to make 8 equal pieces. Handling the dough as little as possible, form each piece into a ball. This can be done by gently stretching the top of a piece of dough to its underside all around. Very lightly coat each ball with flour so it does not stick to the cutting board.
Form the first four dough balls into thick 12-inch strands by holding up a ball in your hands and gently squeezing it between your thumb and other fingers to elongate it into a thick snake. When it is almost the right size, roll it out on a board or directly on the countertop to smooth its sides and slightly lengthen it. If possible, use no flour for rolling, as floured dough is slippery and will slide rather than roll. Each strand should be either of even thickness its entire length or slightly thicker in the middle and tapering to the ends.
When each strand is finished, coat is completely with a dusting of flour, brushing off any excess. The flour prevents the strands from sticking to the countertop during braiding. It also helps the braided strands keep their definition and not blend together during rising and baking, so the finished challot have nicely separated bumps.
Lay the four strands on the countertop, parallel to each other and about 1/2 inch apart. Squeeze the strands together very tightly at one end so they cannot unravel during rising and baking. Braid them by starting with the first strand on the right. Lift it over the two strands next to it and then put it back under the strand on its immediate right. Do this compactly so the overlapping strands stay close to the pinches end. Then do the same with the other side, beginning with the far-left strand. Continue alternating in this way until completely braided. Handles the strands gently and do not stretch or pull them as you braid. When the strands are too short to continue braiding, pinch them very tightly together so that the load cannot unravel during baking.
Tuck both ends slightly under so you cannot see where they strands were pinched, and push the ends of the load together gently to slightly compact it and make it higher in the center. The load should be relatively short and fat; the finished challah will be much larger. Repeat with the second loaf.
Gently transfer the loaves to a large, heavy, flat, shiny aluminum baking sheet that has been greased, coated with non-stick spray, or lined with parchment. An insulated sheet is best.
When both loaves are formed and on the baking sheet, use a pastry brush to coat them well with the reserved egg substitute or the remaining whole egg beaten with 1 tsp water. Sprinkle the tops lightly with poppy seeds or sesame seeds. Turn your oven on to 200 degrees and immediately set a timer for 1 minute. Turn off the oven after exactly 1 minute. Quickly place the baking sheet with the loaves on a middle rack of the barely warm oven, and let the loaves rise for 30 minutes.
Leave the loaves in the oven, and turn the temp up to 350 degrees. Bake the loaves for 32-40 min or until they are golden brown (if using egg substitute they will not be as dark as they are with whole egg or egg yolk glaze). The loaves should make a hollow sound when thumped on the bottom (or be 190-205 degrees when an instant-read thermometer is inserted into the bottom).
Immediately remove the loaves from the baking sheet, and cool them on wire racks for at least 1 hour before eating them. If you're not using the loaves within a few hours, cool them completely; then put each one in an airtight plastic bag or use plastic wrap and freeze them. That the frozen loaves in their wrappers. Thawed loaves may be warmed, wrapped in foil, in a low oven for a few minutes.
For a richer egg challah, use whole eggs (not egg substitute), and increase the sugar and oil to 1/2 cup each. The top may be glazed with 1 or 2 egg yolks beaten with a few teaspoons of water.