Coat an 8 ½ or 9-inch loaf pan, preferably metal, lightly with cooking spray. Sprinkle the bottom and sides with finely ground yellow cornmeal if using and shake and tilt to coat; tap out the excess cornmeal.

Whisk 4 cups all-purpose flour, 2 (¼-ounce) packets instant yeast, 1 tablespoon granulated sugar, 1 ¾ teaspoons kosher salt, and ¼ teaspoon baking soda together in a stand mixer.

Whisk 1 ¼ cups whole milk, ¼ cup water, and 2 tablespoons olive oil together in a small saucepan. Heat over medium heat until warm to the touch (120°F to 130°F), about 2 minutes.

Pour into the stand mixer. Beat with the paddle attachment, starting on low speed and gradually moving up to medium speed, until a tacky dough that clears the sides of the bowl forms (a finger pressed into the dough should not stick), 2 to 4 minutes.

Remove the dough from the bowl and shape it into a ball. Place in the loaf pan and gently push down with damp hands to fill the pan in an even layer, making sure to go all the way to the corners. Sprinkle with 1 teaspoon yellow cornmeal if using.

Coat a sheet of plastic wrap with cooking spray. Place sprayed-side down over the pan. Let rise in a warm place until the dough has risen to just over the rim of the pan by about ¼-inch, 45 minutes to 1 hour. About 20 minutes before the dough is ready, heat the oven to 400ºF.

Uncover and bake until the top is golden brown and an instant-read thermometer inserted into the center registers at least 190°F, 30 to 35 minutes. For a shiny top, immediately brush the top with 1 tablespoon melted butter. Let cool for 5 minutes. Flip the bread out onto a wire rack and let cool completely, about 1 ½ hours. The bread is best served sliced and toasted.