Adjust oven rack to upper-middle position and heat oven to 450 degrees. Line rimmed baking sheet with aluminum foil.
Cut 1 (24 by 4-inch) loaf soft French bread in half crosswise, then halve each piece horizontally to create 4 equal pieces. Arrange pieces cut side down on prepared sheet. Brush crust with 1 tablespoon extra-virgin olive oil.
Combine 8 tablespoons unsalted butter, melted; 2 teaspoons granulated garlic; ½ teaspoon table salt;and ¼ teaspoon red pepper flakes in bowl. Flip bread cut side up and brush cut side evenly with melted butter mixture.
Bake, cut side up, until browned around edges, about 5 minutes.
Meanwhile, combine 1½ cups canned crushed tomatoes, 1 tablespoon extra-virgin olive oil, 1½ teaspoons Italian seasoning, ½ teaspoon sugar, ½ teaspoon table salt,and ½ teaspoon pepper in bowl. (Sauce can be refrigerated for up to 24 hours.)
Spread sauce evenly over toasted bread, then top with 12 ounces shredded mozzarella cheese,followed by 1 ounce grated Parmesan cheese and 2 ounces thinly sliced pepperoni.
Bake until cheese is melted and spotty brown, about 15 minutes. Let pizza cool for 5 minutes. Serve.
