Line two rimmed baking sheets with parchment paper. Or, for added texture (and to prevent sticking), take 1 cup of cornmeal and divide between the two baking sheets in place of parchment. Set aside.

In the bowl of an electric stand mixer, stir together the yeast, water, olive oil, and sugar. Let the mixture bloom for 10 minutes.

In a medium-sized bowl, whisk together both flours, garlic powder, and salt. Attach the dough hook to your mixer and gradually add the dry ingredients to the yeast mixture on low speed. The dough will come together and start to look a bit shaggy. Turn speed to medium-low and knead until the dough is smooth and elastic but still sticky, about 5 minutes. You can also slightly moisten your hands with oil and knead by hand for about 10 minutes. Transfer the dough to a large, lightly oiled bowl, turning to coat. Cover with a damp cloth or plastic wrap, and let rise in a warm place until doubled in size, about 30 minutes to 1 hour.

Gently deflate the dough and turn it onto a lightly floured surface. Using a floured bench scraper, divide the dough into 6 equal pieces, each weighing around 250 grams. Stretch each portion into a tight ball, pinching the bottom with your fingers and rolling around on the counter to seal and shape. If the ball is shaped too loosely it may deflate while baking, so be sure to make a nice tight shape.

Place 3 balls onto each prepared baking sheet. Slash the top with a sharp knife to score in an X shape. Cover and let rise again until doubled in size, about 30 minutes.

Meanwhile, preheat the oven to 400°F and place an empty broiler tray on the top shelf.

In a small bowl, beat the egg with 1 tablespoon of water. Brush evenly over the shaped bread bowls.

Place baking sheet on the center rack. If both baking sheets fit into your oven, place them both on the center rack; otherwise, bake one at a time.

Let the bread bowls cool completely on the pan. Cut a large round from the top of each loaf and scoop out the center. Fill with hot creamy soup and serve immediately.