Line 2 large baking sheets with parchment. In a large bowl, whisk flour and salt.

In a small bowl, stir water, oil, granulated sugar, and yeast. Pour into flour mixture and mix with a rubber spatula until just combined. Knead with your hands until dough is smooth and elastic, 3 to 4 minutes.

Grease another large bowl with oil. Transfer dough to bowl and toss to coat with oil. Cover with plastic wrap or a clean towel. Let dough rise at room temperature until doubled in size, 60 to 90 minutes.

Punch dough down and divide into 2 pieces. On a lightly floured surface, roll each piece to a large rectangle about 12"-by-10". Spread marinara sauce over dough. Sprinkle each with ½ teaspoon oregano, ¼ teaspoon garlic powder, Parmesan, and ½ cup mozzarella. Shingle pepperoni slices over cheese in an even layer.

Starting from the long side, carefully roll dough into a tight log. Arrange logs on a baking sheet seam side down and refrigerate 30 minutes.

Preheat oven to 425°. Transfer logs to a cutting board. Brush with oil, then sprinkle with salt.

Place cornmeal in a small dish. Using a serrated knife, slice log into 12 (1"-thick) slices. Dip bottom cut sides in cornmeal. Arrange on a baking sheet, cornmeal side down, spacing 2" apart.

Bake rolls, rotating pans halfway through, until slightly risen and bottoms are golden brown, 18 to 20 minutes.

Top with basil (if using). Serve with marinara sauce alongside for dipping.