In the bowl of a stand mixer, combine the water, sugar, and yeast. Let sit for 5 to 10 minutes until the yeast is foamy.
Add the salt, oil, and 2 cups of the flour, mixing well with the paddle attachment to combine. Continue to add the remaining flour, 1 cup at a time, switching to the dough hook partway through, until a nice soft dough forms. You may not need all of the flour.
Knead for 5-6 minutes on medium speed until the dough is smooth and cleans the sides of the bowl. It shouldn't be too sticky.
Transfer to a lightly greased bowl and cover with plastic wrap. Let rise in a warm spot for about 45 minutes until doubled in size.
Punch down the dough to remove air bubbles and turn the dough out onto a clean surface and divide into 8 equal pieces. Roll each piece of dough into a ball and transfer to baking sheets lined with parchment paper, leaving space for the dough to rise.
Loosely cover with plastic wrap and let the dough rise for another 30-45 minutes until doubled in size again.
Preheat oven to 400 degrees F while the bread bowls are rising. Make an egg wash by whisking the egg and milk together in a small bowl. Brush it onto the risen bread bowls just before putting them in the oven.
Bake for 22-26 minutes until golden brown on top. Cool for 15 minutes, then use a sharp serrated knife to cut lids off the top of each "bowl". Remove some of the bread inside the bread bowl to make space for soup.