In a large bowl, combine sourdough starter and water until incorporated. Sprinkle yeast over the surface and let sit about 3 minutes. Add flour and salt and stir until dough comes together.

Transfer dough to the bowl of a stand mixer fitted with a dough hook. Knead dough on medium-low speed until smooth and elastic, about 5-7 minutes. (You can certainly also do this by hand as I often do.)

Loosely cover bowl with plastic wrap until doubled in bulk, about 2 hours.

Divide dough in half and shape into loaves. Arrange loaves in proofing baskets or on a board or baking sheet sprinkled generously with cornmeal. Cover and let rise until nearly doubled, about 1 hour.

Place a baking stone on the center rack and preheat oven to 425°F while loaves are rising.

Transfer dough from proofing baskets (if using) onto a board sprinkled generously with cornmeal. Cut slits in top of dough using a very sharp knife or razorblade.

Once oven has been heated to 425°F for at least 30 minutes, carefully slide the dough onto the hot baking stone.

Bake 30 minutes or until deep golden.

Transfer to wire rack to cool completely before slicing.