Step 1: Melt 2 tablespoons of unsalted butter in a medium saucepan over medium heat. Add ¼ cup grated onion, ¼ teaspoon dried oregano, and ½ teaspoon salt. Cook, stirring frequently, until the onion is soft, about 5 minutes.
Step 2: Stir in 2 minced garlic cloves and cook for another 30 seconds until fragrant. Add the 28-ounce can of crushed tomatoes and ¼ teaspoon sugar. Bring the mixture to a simmer.
Step 3: Reduce heat to low and let the sauce cook for 25–30 minutes, stirring occasionally, until thickened. Remove from heat and stir in 2 tablespoons of chopped fresh basil and 1 tablespoon olive oil. Season with freshly ground black pepper to taste. Set aside to cool.
Step 4: Preheat your oven to 425°F (220°C). Roll out your prepared dough (from a separate dough recipe) into a 14-inch circle. Carefully transfer it to a greased 12-inch deep-dish pizza pan, pressing the dough against the sides to form a crust.
Step 5: Spread 1 pound (4 cups) of shredded mozzarella cheese evenly over the dough base. Layer pepperoni slices over the cheese or add your favorite toppings.
Step 6: Spoon the prepared tomato sauce evenly over the toppings, spreading it to the edges. Sprinkle ¼ cup of grated Parmesan cheese on top of the sauce.
Step 7: Place the pizza in the oven and bake for 20–25 minutes, or until the crust is golden and the cheese is bubbly. Let the pizza cool for 5–10 minutes before slicing to allow it to set.