INGREDIENTS:
For the Dough:

3¼ cups all-purpose flour
½ cup yellow cornmeal
1½ teaspoons salt
2 teaspoons sugar
2¼ teaspoons instant yeast
1¼ cups water, room temperature
3 tablespoons unsalted butter, melted
4 tablespoons unsalted butter, softened
1 teaspoon + 4 tablespoons olive oil, divided
For the Sauce:

2 tablespoons unsalted butter
¼ cup grated onion
¼ teaspoon dried oregano
½ teaspoon salt
2 garlic cloves, minced
1 (28-ounce) can crushed tomatoes
¼ teaspoon sugar
2 tablespoons coarsely chopped fresh basil
1 tablespoon olive oil
Freshly ground black pepper
For the Toppings:

1 pound mozzarella cheese, shredded (about 4 cups)
(Pepperoni)
¼ cup grated Parmesan cheese
HOW TO MAKE HOMEMADE CHICAGO STYLE DEEP DISH PIZZA
Make the Dough: Whisk together the flour, cornmeal, salt, sugar, and yeast in a large bowl.
Add water and melted butter and mix on low speed, using a dough hook, until fully combined, 1 to 2 minutes, scraping sides and bottom of bowl occasionally. Increase speed to medium and knead until the dough is glossy and smooth and pulls away from sides of the bowl, 4 to 5 minutes. (You can easily make this by hand, mixing in the water and butter with a spatula and then kneading by hand.)

Coat a large bowl with 1 teaspoon olive oil. Using a greased spatula, transfer the dough to the bowl, turning to coat the dough in oil; cover tightly with plastic wrap. Let rise at room temperature until nearly doubled in volume, 45 to 60 minutes.
Make the Sauce: While dough rises, heat the butter in a medium saucepan over medium heat until melted. Add onion, oregano, and salt; cook, stirring occasionally until liquid has evaporated and onion is golden brown, about 5 minutes. Add garlic and cook until fragrant, about 30 seconds.