For the Biga

• In the bowl of a stand mixer fitted with the dough hook, combine the flour, water and yeast. Mix on low speed until thoroughly combined, about 3 minutes. Transfer the mixture to a large bowl, cover with plastic wrap and allow to rise in a warm place until bubbly, airy, and just starting to recede, about 8-10 hours.
• For the Final DoughIn the bowl of a stand mixer fitted with the dough hook, combine the flour and yeast. Add the water, biga, and salt and mix on low speed for 3 minutes. Increase the speed to medium and knead until the dough is blended, about 3 minutes more. The dough should be wet and slack.
• Transfer the dough to a lightly oiled bowl, turning to coat, cover with plastic wrap and let rise until nearly doubled in size, about 30 minutes. After 30 minutes, press the dough with a fingertip; the indentation should not fill in rapidly.  Fold the dough over on itself by lifting the edges up and over the center and pressing gently to release the gas. Allow the dough to rest for another 15 minutes.
• Turn the dough out onto a floured work surface and dust the top with additional flour. Using your palms, gently press the dough into an 8x9-inch rectangle that is an even 1-inch thick. Cut the dough into two 8 x 4½-inch rectangles. Cover the dough with a kitchen towel and let rest again for 15-20 minutes. Gently free the dough from the surface, trying not to tear or stretch the dough. Transfer the dough to a large parchment lined baking sheet. Gently stretch each piece into a 10 x 4½-inch rectangle. Cover and let the dough rise in a warm, draft free space for 30-45 minutes.
• Meanwhile, preheat the oven to 425ºF. Bake the ciabatta until golden brown and the crust sounds hollow when thumped on the bottom, about 25-30 minutes. Transfer to wire racks to cool completely. Enjoy!