Pour the warm water over yeast in the bowl of a stand mixer fitted with a dough hook attachment. Or, if you don't have a stand mixer, a regular large mixing bowl. Whisk together and allow to sit for 5 minutes. Cover the bowl with a towel. The mixture should be frothy and foamy after 5 minutes.
If you do not have a mixer, you can mix by hand in this step. With the stand mixer running on low speed, add the sugar, salt, olive oil, 4 cups of bread flour, and seasonings (if using, see recipe note). Beat on low speed for 1 minute, then add remaining 2 cups of flour. Beat on low speed for 5-6 minutes. The dough should be thick, yet soft. And only slightly sticky. It should pull away from the sides of the bowl as it mixes. If it's too sticky, add more flour, 1 tablespoon at a time, until it pulls away from the sides of the bowl.
Form dough into a ball and turn it out onto a lightly floured surface. And place into a large greased bowl, turning once to grease the top. (I just use the same mixing bowl-- remove the dough, grease it with nonstick spray or olive oil, put the dough back in.) Cover the bowl with plastic wrap and place it in a warm environment to rise until doubled, about 90 minutes.
Once doubled in size, punch down the dough to release any air bubbles. Remove dough from the bowl and turn it out onto a lightly floured surface. Punch down again to release any more air bubbles if needed.
Using a sharp knife or dough scraper, cut into 6 even pieces. Form each into a large ball.
Line 2 large baking sheets with parchment paper or silicone baking mats. Place 3 dough balls onto each. Cover lightly and set aside to rest for 20 minutes as the oven preheats.
Preheat oven to 400°F (204°C). Brush each dough ball with egg wash and, using a sharp knife, score an X into the tops of each.
Bake for 30 minutes or until golden brown. Cool until ready to handle. The longer you cool, the easier they are to cut open!
For serving, cut a large round out of the top of each bread bowl. Scoop out the center (save the center to dunk into soup!) and fill with soup.
Cover and store leftover bread bowls at room temperature for a couple days or in the refrigerator for 1 week. You can also freeze the baked bread bowls for up to 3 months, then thaw overnight in the refrigerator. Bring to room temperature before serving.