In a large mixing bowl, combine flour, cornmeal, sugar, salt, and yeast. Add melted butter, olive oil, and warm water. Mix until a sticky dough forms.
Knead the dough for about 6 to 8 minutes by hand or in a stand mixer with the dough hook until smooth and elastic.
Place the dough in a greased bowl, cover, and let it rise in a warm place for 1 hour or until doubled in size.
While the dough rises, make the sauce. In a saucepan over medium heat, add olive oil and garlic. Cook for 1 minute, then stir in crushed tomatoes, sugar, salt, pepper, and basil. Simmer on low for 20 minutes, stirring occasionally.
In a skillet over medium heat, add olive oil and cook the sausage, breaking it into crumbles, until browned. Drain and set aside.
Preheat the oven to 425°F (218°C).
Roll the dough out into a circle about 12 inches in diameter. Press it into your greased 9 inch deep dish pan, pushing it up the sides.
Begin layering your fillings: first add shredded mozzarella cheese to cover the bottom, then add cooked sausage, pepperoni, green peppers, onion, and dried oregano.
Pour the tomato sauce over the top and spread evenly. Sprinkle with grated Parmesan cheese.
Bake the pizza on the lower rack of your oven for 35 to 45 minutes, until the crust is golden brown and the sauce is bubbling.
Let the pizza cool for 5 to 10 minutes before slicing and serving.