Mix the Dry Ingredients: Combine the strong white flour and cornmeal flour in a medium bowl. Stir in the dried yeast and fine salt until evenly distributed.
Form the Dough: Pour the warm water into the flour mixture and stir with a wooden spoon until everything comes together into a sticky dough.
Shape the First Dough Ball: Lightly flour your hands using some of the extra flour, then shape the sticky dough into a rough ball. Transfer it to a clean bowl and dust the surface lightly with flour.
First Rise: Cover the bowl and leave the dough in a warm place until it has doubled in size. This should take about 1 hour, although the dough should be checked as it rises.
Knock Back the Dough: Lightly flour your work surface. Punch down the risen dough with your hands to deflate it, then transfer it onto the floured surface.
Divide the Dough: Shape the dough roughly into a ball, then use a dough scraper or knife to cut it in half.
Shape the Loaves: Form each portion into a smaller rough ball, approximately 15–20 cm wide.
Prepare for the Second Rise: Lightly oil a large baking tray and place the two dough balls on it. Sprinkle the loaves with additional flour; this helps create the characteristic crackled effect on the surface.
Second Proof: Cover the dough loosely with a tea towel and leave it in a warm place for about 30 minutes, or until the loaves have doubled in size.
Bake the Bread: Preheat the oven to 200°C. Bake the risen loaves for 35 minutes, or until the bottoms sound hollow when tapped.
Cool or Serve Warm: Remove the baked loaves from the oven and allow them to cool, or serve them warm.
