Step 1: Prepare the Dough

1. In a mixing bowl, combine flour, cornmeal, salt, and instant yeast.
2. Add warm water, melted butter, and olive oil, then mix until a dough forms.
3. Knead for about 7-10 minutes, until smooth and elastic.
4. Place the dough in a greased bowl, cover with a towel, and let it rise in a warm place for 1-2 hours, or until doubled in size.

Step 2: Make the Tomato Sauce

1. Heat olive oil in a saucepan over medium heat.
2. Sauté the chopped onion until soft, about 3 minutes. Add the garlic and cook for another 30 seconds.
3. Pour in the crushed tomatoes, then stir in oregano, basil, sugar, salt, and red pepper flakes.
4. Simmer for 15-20 minutes, stirring occasionally, until the sauce thickens.

Step 3: Assemble the Pizza

1. Preheat the oven to 425°F (220°C).
2. Roll out the dough into a large circle, about 2 inches bigger than your pan.
3. Press the dough into the greased deep-dish pan, making sure it goes up the sides.
4. Layer the bottom with shredded mozzarella cheese.
5. Add any toppings (pepperoni, sausage, or veggies).
6. Pour the tomato sauce over the toppings, spreading it evenly.
7. Sprinkle Parmesan cheese on top.

Step 4: Bake the Pizza

1. Place the pizza in the oven and bake for 25-30 minutes, or until the crust is golden brown and the cheese is bubbly.
2. Let it cool for 5-10 minutes before slicing.