In a large mixing bowl, combine the active sourdough starter and warm water. Mix with a spoon or your hand until the starter is mostly dissolved.

Add the bread flour and salt to the bowl. Mix until just combined and no dry spots of flour remain. The dough will be shaggy. Cover the bowl with plastic wrap or a damp towel and let it rest for 30 minutes (autolyse).

After the autolyse, add the 1 tbsp of olive oil. With wet hands, gently incorporate the oil into the dough. Perform a set of 'stretch and folds': grab a portion of the dough, stretch it upwards, and fold it over itself. Rotate the bowl and repeat this 4-6 times until the dough tightens up. Cover and rest for 30 minutes.

Repeat the stretch and fold process 2-3 more times, with 30-minute rests in between each set. You should notice the dough becoming smoother, stronger, and more elastic with each set.

After the final stretch and fold, cover the bowl and let the dough bulk ferment at room temperature (around 70-75°F / 21-24°C) for 2-4 hours, or until it has visibly increased in volume by about 20-30%. The exact time will depend on your starter's activity and ambient temperature.

Lightly oil two separate containers or bowls. Gently transfer the dough onto a lightly floured surface. Divide the dough into two equal pieces using a dough scraper or knife. Gently shape each piece into a taut ball by cupping it with your hands and rotating it on the counter.

Place each dough ball into its oiled container, cover tightly, and refrigerate for 12-24 hours for a slow cold fermentation. This step significantly develops flavor and texture.

About 2-3 hours before baking, remove the dough balls from the refrigerator and place them on a lightly floured surface. Let them come to room temperature, covered loosely with plastic wrap, which makes them easier to work with.

Preheat your oven with a pizza stone or steel inside to its highest possible temperature (usually 500-550°F / 260-290°C) for at least 60 minutes. This is crucial for a crispy crust.

Generously dust a pizza peel with semolina flour or regular flour to prevent sticking. Take one dough ball and gently stretch it from the center outwards, using your fingertips to create an even crust and leaving a slightly thicker edge. Do not use a rolling pin. If the dough resists, let it rest for 5-10 minutes before continuing.

Carefully transfer the stretched dough onto the prepared pizza peel. Quickly add your desired toppings: spread pizza sauce evenly, leaving the crust exposed. Top with mozzarella and any other desired ingredients.

Slide the pizza from the peel directly onto the preheated pizza stone/steel in the oven. Bake for 8-15 minutes, or until the crust is golden brown and bubbly, and the cheese is melted and lightly browned. Baking time will vary based on your oven.

Remove the pizza from the oven using the peel. Garnish with fresh basil leaves, a drizzle of extra virgin olive oil, and red pepper flakes if using. Let cool for a minute or two before slicing and serving. Repeat with the second dough ball.