Whisk together flour, salt, and yeast in a large mixing bowl. Add warm water. Beat with electric, fitted with dough hook, on low just until combined. Let rest in bowl for 10 minutes or until dough is smooth and elastic.

Shape dough into a ball. Lightly grease a large, clean bowl with olive oil. Place dough in bowl; turn over to grease surface. Cover dough loosely with plastic wrap. Let rise in a warm, draft-free place about 2 hours or until double in size.

Place 2 tablespoons olive oil in a 13x9-inch baking pan; tilt pan to coat bottom. Turn dough out into prepared pan; pat dough in bottom and 1 inch up the sides of the pan. Cover with plastic wrap and let rest for 1 hour.

Preheat oven to 500°. Scatter both mozzarella cheeses on dough; lightly pat into bottom and sides of the dough. Layer with green pepper and both pepperoni slices. Drizzle with pasta sauce. Bake 15 to 20 minutes or until sides are crispy and cheeses are bubbly. Let stand 5 minutes before serving. Cut into 12 slices.