Directions

• Stir together flour, water, and yeast in a small bowl, forming a sticky dough. Cover bowl tightly with plastic wrap, and refrigerate for at least 12 hours or up to 24 hours. (Biga will rise slightly.)
• Place Biga, oil, sugar, yeast, salt, and 1 cup of the water in the bowl of a stand mixer fitted with a paddle attachment. Beat on low speed until mixture looks creamy, about 1 minute. Add flour, beating on low speed. Increase mixer speed to medium, and beat until dough starts to pull away from sides of the bowl, about 2 minutes. Switch to a dough hook attachment, and beat on medium speed until smooth and elastic, about 8 minutes. Transfer dough to a large greased bowl, and cover with plastic wrap. Let stand in a warm place until almost doubled in size, about 2 hours.
• Stir together baking soda and remaining 1 tablespoon water in a small bowl until combined. Punch dough down, and stir in baking soda mixture until combined (it will be streaky).
• Brush an 8 1/2- x 4 1/2-inch loaf pan with 1 tablespoon of the melted butter. Transfer dough to prepared loaf pan, and cover with greased plastic wrap. Let stand in a warm place until almost doubled in size, about 1 hour.
• Preheat oven to 375°F. Uncover dough, and brush with remaining 1 tablespoon melted butter, and sprinkle with cornmeal. Bake in preheated oven until golden brown, about 30 minutes. Let cool in loaf pan 5 minutes; invert onto a wire rack, and brush with any remaining butter. Let cool completely, about 1 hour.