Method

• Prepare the biga: Using an electric hand or stand mixer, fitted with dough hooks, and a medium-size bowl, mix flour, yeast, and water on low speed until mixture forms shaggy dough, 2 – 3 minutes. Cover tightly with plastic wrap and let stand at room temperature until the sponge begins to bubble and rise, for about 3 hours. Then, refrigerate the sponge for at least 8 hours or up to 24 hours.
• Prepare the dough: Take sponge out of the refrigerator and let stand at room temperature while you are making the dough. Using a mixer, fitted with hooks, mix flour, yeast, and water on low speed until a scrappy dough forms, about 3 minutes. Cover the bowl with plastic and set aside for 20 minutes.
• Add sponge and salt to the dough and knead on low speed until the ingredients are well incorporated and a smooth dough forms, about 4 – 5 minutes. The dough should clear the sides of the bowl but stick to the bottom. Increase the mixer speed to medium and continue to knead until the dough is smooth and elastic, about 1 minute. Cover the bowl tightly with plastic wrap and let the dough rise at room temperature until doubled in size, about 1 hour.
• Stretch and fold: Dip your hand in water. It will prevent the dough from sticking to your hand. Then push your hand deep under the dough, pull the dough to you and fold over the rest of the dough. Repeat the process from all sides until the whole dough is folded and lies round and tight in the bowl. Cover the bowl with plastic wrap and let the dough rise for 1 hour. Repeat stretching and folding, cover and let the dough rise for 1 hour longer.
• Shape the loaf: Top pizza peel with parchment paper. Transfer the dough onto a well-floured workspace. Dust the dough and your hands generously with flour and gently stretch the dough into a 10-inch square. Fold top right corner to the middle, then repeat the step with the left corner. Begin to gently roll the dough from top to bottom. Form a log and press on the seam with your fingers. Gently transfer the formed dough to the prepared pizza peel , seam side down and gently tuck into a taut loaf. Spray or brush with vegetable oil, cover loosely with plastic and let rise at room temperature until almost doubled in size, 1 – 1.5 hours.
• Bake: One hour before baking, adjust the oven rack to lower-middle position, place baking stone on rack and heat the oven to 500F / 260C. Using a sharp serrated knife or a bread lame, make three diagonal slashes, along the top of the loaf. Spray the loaf with water and slide parchment with loaf onto the baking stone. Bake for 10 minutes, then reduce the oven temperature to 400F / 200C and continue to bake until the crust is deep golden brown, about 35 minutes longer. Transfer the loaf onto a wire rack, discard parchment paper and let cool completely, about 2 hours, before slicing and serving.