Instructions

Grease large bowl. Grease two 8 1/2 by 4 1/2-inch loaf pans and dust with extra cornmeal. Whisk water, molasses, and melted butter in bowl or large measuring cup until combined.
Using stand mixer fitted with dough hook, mix flour, yeast, salt, and cornmeal on low speed until combined, about 5 seconds. Slowly add molasses mixture and knead until cohesive mass starts to form, about 2 minutes. Increase speed to medium-low and knead until dough is smooth and elastic, 6 to 8 minutes. (Dough should clear sides of bowl but will stick to bottom.) Turn out dough onto lightly floured counter and knead for 1 minute.
Transfer dough to prepared bowl and cover with plastic wrap. Let rise at room temperature until almost doubled in size and fingertip depression in dough springs back slowly, 1 to 1 1/2 hours.
Gently press down on center of dough to deflate. Place dough on lightly floured counter and divide in half. Working with 1 half at a time, pat dough into 17 by 8-inch rectangle. With short side facing you, roll dough away from you into firm cylinder. Pinch seam closed. Place loaf seam side down in prepared pan, pressing gently into corners. Repeat with remaining dough.
Cover loaves loosely with plastic and let rise at room temperature until almost doubled in size, 1 to 1 1/2 hours (tops of loaves should rise about 1 inch above lips of pans). About 20 minutes before dough is fully risen, adjust oven rack to lower-middle position and heat oven to 425 degrees.
Place pans in oven and reduce oven temperature to 375 degrees. Bake until crust is brown and bread registers 200 degrees, 35 to 45 minutes, switching and rotating pans halfway through baking. Turn out loaves onto wire rack and let cool completely before serving, about 2 hours.