Ciabatta means “slipper,” and this loaf is shaped like one. This shape, along with the airy crumb and crisp crust, are a direct result of this dough's high moisture content. It's a wet one!

1. To create the sponge, combine water and yeast. Stir to dissolve and let stand 5 minutes. Add whole wheat flour and beat for 1 minute. Cover and let stand at room temperature 8–12 hours.

2. Add to the sponge the milk, ¼cup olive oil, 1 teaspoon salt, and bread flour. Beat by hand or electric mixer for 5–6 minutes, until elastic. The dough will be very loose. Cover with plastic, and leave at room temperature until doubled in volume, about 1 hour.

3. Line a baking sheet with parchment, brush with olive oil, and sprinkle with cornmeal. Turn risen dough gently onto a floured surface and divide into 2 equal portions. Transfer to prepared pan and shape each into a flat oval, using oiled hands. Press fingertips into dough to create dimples. Cover again with plastic and rise until doubled, another 1½ hours. Preheat oven to 475°F.

4. Brush the top of the risen loaves with olive oil and a pinch of salt, and bake until golden brown and hollow sounding, about 20–30 minutes. Cool completely on a rack.