Use large counter electric mixer with dough hook at slow speed.
Place 4 cups of flour in the mixing bowl, make indentation into flour, and place yeast and sugar in indentation.
Add ½ cup of water and mix. Include some flour in the mix. When sponge rises, add eggs one at a time and blend thoroughly. Then add salt, remainder of the flour along with water at 110°, oil, and sugar. If batter is too loose add flour and bring dough to an elastic state.
Remove from machine and knead 3 to 4 minutes. Place in a greased bowl, cover, and let rise to double in size. Remove from bowl and cut in half.
Challah requires 6 braids, however, a 3 strand braid is easier. Form each half of the dough into equal pieces and form 6 strands at 14” to 18” long.
Double braid and place on corn meal covered cookie sheet. Slightly beat the egg and cold water to make an egg wash. Brush egg wash on top of leaves and and then sow seeds on top.
Pre-heat oven to 400°F. In the meantime let the loaves rise the second time for about 1 hour. Bake for 15 minutes then change the temperature to 350°F. Baking time should be about 30 minutes.