In a mixing bowl, dissolve the yeast into the 1/3 cup warm water and mix in the one teaspoon of sugar. Let the mixture sit for ten minutes, or until it thickens. Meanwhile, in a separate medium bowl, combine the 2/3 cup of sugar, salt, 2¾ cups of bread flour and corn meal. Set aside.
When the yeast is thick, add the ½ cup of oil, 2 eggs and ½ cup of warm water then mix well with a whisk. Add the dry ingredients and mix well with a wooden spoon. You can use the dough hook of a stand mixer if you prefer.
Sprinkle 1 tablespoon of the flour on your counter and place the dough on top. Knead until you have a smooth and silky dough, adding another tablespoon of flour if necessary.
Grease the mixing bowl with the remaining 1 teaspoon of oil, return the dough to the bowl and rub your oiled hands on top of the dough. Cover the bowl with a dish towel and let the dough rise for 1 hour.
Shape the dough into a three-braided challah (see Recipe Notes). Place the loaf on a parchment-lined pizza peel (see Recipe Notes) and it let rise for 45 minutes.
While the dough is rising, preheat your oven to 350° F. If using a pizza stone, put it in a cold oven and preheat it with the oven.
Place the remaining egg into a small bowl, add just under 1 teaspoon water and beat well. Brush the egg mixture on top of the loaf/loaves and sprinkle the pumpkin seeds on top. Bake for 30 to 35 minutes, or until golden. I made one loaf and it took 35 minutes.
Cool completely on a wire cooling rack.