Stir the yeast into ½ cup of the warm water. Let proof as you measure out the dry ingredients.
Combine 5 cups flour, sugar and salt in the bowl of an electric mixer. Add the yeast mixture, remaining water, and olive oil. Using a dough hook attachment, mix on the lowest speed of electric mixer (stir setting on a KitchenAid) until a dough starts to form, adding more flour as needed, up to an additional ¾ cup. Knead on low speed (2 on a KitchenAid) for 7 minutes. Transfer dough to a lightly floured surface and knead by hand for 1 to 2 minutes, or until a smooth, firm, elastic dough is formed.
Transfer the dough to a lightly oiled bowl and spray the dough with a thin coating of cooking spray. Wrap the bowl with plastic wrap and set aside to proof in a warm, draft-free place for 1½ hours or until doubled in size.
Remove the plastic wrap, punch down and flatten the rounded dough with the heel of your hand. Roll the dough up tightly, sealing the seam well after each roll. The dough should be elongated and oval-shaped, with tapered and rounded (not pointed) ends.
Place a baking stone on the center oven rack and preheat the oven to 425°F. Place a metal baking pan on the lowest rack.
Place the dough on a baker's peel heavily dusted with flour, or alternately on an inverted baking sheet. Allow the dough to proof, loosely covered with a floured dish towel, for 30 minutes, or until doubled in size.
If using the topping, brush the dough with the egg white and sprinkle the sesame seeds over the top. Using a razor blade or sharp knife, slash the dough lengthwise about 1/4-inch deep, keeping the blade at a 45-degree angle.
Just prior to placing the bread in the oven, pour 1 cup of water into the metal pan you placed on the bottom rack of the oven. Then, transfer the loaf from the peel to the stone in the oven.
Bake the dough until golden brown and a hollow thud is heard when tapping the bottom of the bread (it should register at least 195 degrees F on an instant-read thermometer), about 30 to 40 minutes. Allow the bread to cool before slicing.
Bread Flour - I outlined above why I'm a big advocate of bread flour for this particular recipe; you can find it in nearly all grocery stores or can buy it online. If you substitute all-purpose flour, there will be a definite difference in texture.
Yeast - This recipe calls for active dry yeast, but you can substitute instant yeast without an issue or any modifications.
Mixing by Hand - While using a stand mixer with dough hook makes this easier, you can absolutely mix and knead entirely by hand.
Extra Flour - Note that the recipe states you may need to add a little extra flour during the mixing process to get a dough to come together. I find that this varies during different times of the year, as well as what the weather is like. If it's warmer/more humid, you may need more flour. When it's colder and drier, I rarely, if ever, need to add more flour.
Metal Pan - I want to emphasize once more that the pan you place on the bottom rack of the oven to create steam needs to be METAL and not glass.
Baking Stone - This is the baking stone that I use, and this is the pizza peel you see pictured above. If you don't have a baking stone, you can flip a baking sheet upside down and put a sheet of parchment paper on top and bake the bread on there (you would not need to place the pan in the oven during preheating).