In the bowl of a stand mixer fitted with the paddle attachment, stir together flour, Parmesan, sun-dried tomatoes, instant sourdough, and salt by hand.

Add warm water, and beat at medium-low speed until a sticky dough forms, about 30 seconds.

Cover and let rise in a warm, draft-free place (75°F/24°C) for 2 hours; refrigerate for at least 2 hours.

Line a sheet pan with parchment paper, and generously dust with bread flour.

Turn out dough onto a lightly floured surface. To form a boule, gently press dough to an even thickness.

Working clockwise, fold in edges toward center, pressing lightly, to form a ball.

Turn ball over, seam side down. Using both hands, cup dough, and pull toward you.

Turn dough 90 degrees, and repeat until a smooth, tight, sealed boule forms (4 to 5 times).

Place dough on prepared pan. Cover and let rise in a warm, draft-free place (75°F/24°C) for 1 hour.

When dough has 30 minutes left to rise, place a 5- to 7-quart Dutch oven and lid in a cold oven.

Preheat oven to 500°F (260°C).

Using a lame or razor blade, score top of loaf.

Carefully remove hot Dutch oven from oven; remove lid, and place bread, still on parchment, in Dutch oven.

Cover with lid, and place back in oven. Immediately reduce oven temperature to 425°F (220°C).

Bake for 35 minutes. Remove lid, and bake until an instant-read thermometer inserted in center registers 205°F (96°C), about 10 minutes more.

Immediately remove loaf from Dutch oven, and let cool completely on a wire rack.