To make focaccia: in the bowl of a stand mixer, combine yeast with warm water. Let stand until dissolved and begins to foam. About 10 minutes. Add the salt, sugar, 3/4 cup olive oil and 1 cup of flour at a time. Kneed with the dough hook on low speed. Once the dough begins to come off the sides of the bowls and stick to the hook it's done. Remove from the bowl and form a ball. Transfer to a lightly oiled bowl and cover with plastic wrap. Proof the dough in a warm area until it doubles in size. (1h30-2hours)

In a deep dish pan, grease with oil. Turn the dough out into the pan and evenly using your hands into the pan covering the entire surface. Cover once again with a kitchen towel and let rise another hour.

Preheat the oven to 450 degrees. Dimple the dough using your fingers across the entire surface. Be sure to go in as far as you can with your fingers. Make sure that the dough is flat all the way across and even. The edges should all be the same level as the middle and not higher.

To make the sauce: combine tomatoes, oregano, garlic, salt and pepper and chili flakes into a blender or food processor. Blend until smooth and well combined, about 1 minute.

To assemble: Layer mozzarella as the base overtop the focaccia, followed by the sauce, pepperonis, and finish with grated parmesan. Ensure the surface is fully covered. Cook for 25-30 minutes until the pepperonis begin to crisp. For crispier pepperonis broil the bread in the last minute of cooking.

Remove from heat and let rest in the pan until slightly cooled. Remove from the pan and cut into squares. Drizzle a little olive oil over top when serving and extra parmesan. Serve warm or at room temperature.