Dissolve yeast in warm water with a big pinch of sugar.
Place the flour in a large bowl. Add the dissolved yeast and stir with a spoon. Add the remaining sugar, salt, eggs, and vegetable shortening. Beat about 1 minute and then mix by hand. When the dough begins to leave the side of the bowl, turn it onto a lightly floured surface to knead and Knead for about 15 minutes until soft, adding more water or flour as necessary.
Place the dough in a lightly greased bowl, turning the dough over so that the entire surface is lightly greased. Cover with a cloth. Let rise in a warm place for an hour or more , until the dough is doubled . Punch down. Divide into 2 balls.
Preheat Oven to 375°F.
Divide each ball into three pieces. Roll each piece into a (appox 12") strand and braid, then tuck in ends. ( he gives a six strand braiding method that is really confusing so I use the 3 strand method).
Place braid onto either cornmeal sprinkled or parchment paper lined ( I use parchment paper) sheet. Use 3rd egg ( beaten with a bit of water) and brush ( using a pastry brush) the Challah. If using sesame or poppy seeds, sprinkle over at this time. Cover with a plastic sheet ( spray with Pam first) and let rise 30 minutes.
Bake for 15 minutes or until golden brown.