Step 1

In a large bowl, stir together the flour, yeast, salt and rosemary. Add the water and stir until a shaggy, sticky dough forms. Cover the bowl with plastic wrap and set aside at warm room temperature (about 70°F/21°C) until the surface of the dough is dotted with bubbles, about 12 hours.

Step 2

Turn the dough out onto a well-floured surface. Using a bench scraper or your hands, turn the dough over on itself a few times and shape into a ball.

Step 3

Lightly flour the bottom of a 3-quart (3-l) Dutch oven or a no-knead bread pot. Gently transfer the dough to the pot and cover with a towel. Set aside at warm room temperature until doubled in size, about 1 1/2 hours.

Step 4

Preheat an oven to 425°F (220°C).

Step 5

Using a pastry brush, brush the top of the dough with the egg white. Cover the pot and transfer to the oven. Bake for 30 minutes, then remove the lid and continue to bake until the top of the bread is golden brown, 10 to 20 minutes longer.

Step 6

Transfer the pot to a wire rack and let cool for 10 minutes. Turn the bread out onto the rack and let cool completely before serving, at least 1 hour. Makes one 1 1/2-lb. (750-g) loaf. Serves 8.

Step 7

Williams Sonoma Test Kitchen