Proof: Combine water, yeast and 1 tablespoon sugar in a medium bowl until yeast is dissolved. Let stand for 5-10 minutes (a warm spot in your kitchen or even on the open door of a preheated 200F degree oven works!). The mixture will be bubbly and/or foamy (if nothing is happening after 20 minutes, something is wrong with your yeast; discard and start over).
Mix dry: Place flour in a very large bowl and mix to blend. Reserve 2 cups of the flour and set aside for later use. Stir in 2 cups sugar and salt to blend. Push the mixture to the sides of your bowl, creating a well in the center.
Add wet: Pour the yeast mixture, 5 eggs, and oil into the well. Mix with a long mixing spoon until you can no longer stir it.
Knead: Continue to knead the dough by hand until it no longer sticks to the sides of the bowl, while slowly adding in small amounts of flour as needed from the reserved 2 cups. The dough should be smooth and elastic. If the dough is very sticky, add in some more flour (do not exceed using the 2 cups of reserved flour. If you have used up the 2 cups and the dough is still very sticky, add a little bit of oil).
Rise: Rub the top of the dough with oil to coat. Cover with a clean towel; rise for 2 hours, until the dough has doubled in bulk. Punch down, replace towel and rise for another 1½ hours. Punch the dough down again, and turn onto a lightly floured surface. *At this point, you can do the mitzvah of hafrashat challah (separating the dough)Dini's Note: I usually let it rise once for 1-2 hours, punch down, form into shapes and then let it rise again for an hour or so before brushing with egg wash and baking. I like to let it rise again once the challahs are formed to get them as fluffy as possible. Shape: Preheat oven to 350F degrees. Divide the dough into 8 portions (or as many loaves/rolls as you would like to make depending on the size). Shape or braid each portion as desired and place onto prepared baking sheets. Repeat with all remaining dough.
Bake: Brush challahs with egg wash. Sprinkle with sesame seeds, bagel spice, etc. if desired. Bake challahs 25-35 minutes until golden brown and challah sounds hollow when tapped on the bottom. Cool on wire racks.
