Dough 8 Steps
In a food processor, combine bread flour, salt, yeast, olive oil and warm water and process until dough starts to form and circulates with the blade, continue processing for 40 more seconds.
In a blue carbon steel sheet pan or a cast iron sheet pan (measuring around 18" by 13") pour 1/4 cup extra-virgin olive oil into the pan (coating the entire bottom) and transfer the dough from the food processor to the pan. Gently spread out into a rectangular shape (will only cover the centre of the pan at this point) and cover with plastic wrap. Let rise in a warm place for 3-4 hours.
After dough has risen, gently spread the dough out to the corners of the pan by stretching and pulling gently with your fingers. If dough seems difficult to work with, let rest for 10 minutes and stretch again (repeat this process until dough is evenly dispersed in the pan). Set aside for another 30 minutes.
Meanwhile make the sauce by heating up 3 tablespoons of olive oil over medium heat in a heavy-bottomed pot or Dutch oven. Add onions and cook until translucent and soft (roughly 3-5 minutes). Add garlic, oregano, red pepper flakes and a few cracks of freshly ground black pepper. Cook for 1 minute or until garlic softens and spices become fragrant. Add a small pinch of salt. Add tomatoes, breaking them up while you stir and sugar. Stir and bring to a slight simmer and cook for 15 minutes. Season with salt. Turn off heat, set aside and allow sauce to slightly cool.
Position your rack near the bottom of the oven and preheat to 550°F (or as high as your oven goes). If your oven has a powerful bottom burner, keep rack in the centre to avoid burning the bottom of the pie.
Layer your slices of mozzarella evenly over your pie, leaving a 1/2"-inch border. Using a ladle or large spoon, dollop your sauce over the cheese and spread evenly. Be careful not to spoon too much sauce onto your dough (you should have leftover sauce in your pot). Top with a generous amount of pepperoni and sprinkle with 1/4 cup of grated Parmigiano.
Bake in the oven fo 10 minutes (or longer if your oven doesn't go to 550°F) or until dough is golden and crispy on the bottom and cheese has melted and pepperoni starts to curl.
Remove from the oven, top with remaining 1/4 cup of grated Parmigiano and additional red pepper flakes.