1. In a large bowl dissolve the yeast and a pinch of the sugar in 1 cup of the warm water and let stand for 10 minutes. 2. Whisk the oil into the yeast, then beat in two of the eggs, one at a time, with the remaining sugar (reserving 1 pinch) and salt. Gradually add 5 cups of the flour, and more water if necessary. When the dough holds together, it is ready for kneading. (You may also use a mixer with a dough hook both for the mixing and the kneading.) 3. Turn the dough onto a floured surface and knead until smooth and "as soft as a baby's bottom," for about 15 minutes, adding additional flour or water if needed. Clean out the bowl and grease it, then return the dough to the bowl. Cover and let rise for an hour, until doubled in size. Punch down, cover and let rise again for another 30-45 minutes 4. To make 1 large loaf, on a floured board, take two-thirds of the dough and divide it into 3 equal pieces. Roll each piece out into a rope-shape strand as thick as a thumb and then braid the 3 strands together. Then take the remaining third of the dough, divide and shape it into 3 strands and braid. Place the small braid on top of the large one. Let the challah rise again for 30 minutes. 5. To make 2 smaller loaves divide the initial dough in 2 and then proceed for each loaf as you did in step 4. 6. Line a baking sheet with greased wax paper and place the loaf or loaves at least 2 inches apart on the sheet. Preheat the oven to 375 degrees. 7. Beat the remaining egg with the remaining pinch of sugar, and using a pastry brush, coat the loaves in the egg wash. Sprinkle with sesame seeds, if desired. 8. Bake for 35-45 minutes or until golden brown and loaves sound hollow when tapped. Cool the loaves on a rack. Yield: 1 large loaf or 2 smaller loaves