Topping

1. For the dough, in a stand mixer with a dough hook, combine the yeast with 1 teaspoon sugar and ¼ cup warm water. Let stand until frothy, about 10 minutes.
2. Slowly add the 9 cups flour, the remaining sugar and the salt to the bowl, then add the egg, oil and remaining 2½ cups warm water.
3. Mix at low speed for 3–5 minutes, until it comes together. Increase the speed to medium and knead for 7–8 minutes, until the dough is elastic and no longer sticky.
4. Place the dough in a large well-oiled bowl, turning the dough over to make sure it’s fully coated in oil, and cover with a tea towel. Let stand for 1 hour, until doubled in size.
5. Line two rimmed baking sheets with parchment paper. Set aside.
6. Dust the counter with flour and punch the dough down.
7. Divide into two equal portions, then roll each piece into a very thick rope and coil it around itself a couple of times, starting with the top tucked in and then tucking the bottom of the rope under each loaf, sort of like a squat beehive.
8. Place each loaf on a prepared baking sheet. Cover with tea towels and let rise for another 1½ hours, until doubled in size.
9. Preheat the oven to 350°F. Brush the egg yolk and water mixture all over the loaves. Sprinkle generously with brown sugar and pat the surface to make sure it sticks.
10. Bake the loaves one at a time, until golden brown and cooked through, about 35–40 minutes.
11. When done, the loaves should sound hollow when tapped on the bottom. Transfer to a wire rack to cool completely.