Stir the warm water, active dry yeast, and sugar together in a large bowl. Let the mixture stand for about 5 minutes, until the yeast looks foamy.

Mix in the salt and approximately 3 cups of the flour. Add the remaining flour gradually, stirring until a soft, workable dough forms; include the optional olive oil or melted butter if you prefer a softer crust.

Turn the dough onto a lightly floured surface and knead for 5 to 7 minutes, until smooth and elastic. Keep the dough slightly tacky and avoid adding excessive flour.

Cover the dough and let it rest in a warm place for 10 to 15 minutes. This short rest gives the yeast time to begin developing the dough.

Shape the dough into one long loaf or divide it into two smaller loaves. Place the shaped dough on a greased baking sheet dusted with cornmeal, then make several diagonal slashes across the top.

Cover the shaped loaf or loaves and let them rest for another 10 to 15 minutes. Meanwhile, heat the oven to 425°F (220°C); for extra crustiness, place a shallow pan in the oven while it preheats.

Bake for 20 to 25 minutes, carefully adding hot water to the shallow pan when the bread goes into the oven if using the steam method. The bread is ready when deeply golden and hollow-sounding when tapped, or when the center reaches about 190–200°F (88–93°C). Cool for at least 10 minutes before slicing.