1. Preheat oven to 425°. Sauté onion in 1 Tbsp. hot oil over medium-high heat 15 minutes or until golden brown.
2. Press dough into a 15- x 10-inch jelly-roll pan, pressing to about 1/4-inch thickness. Press handle of a wooden spoon into dough to make indentations at 1-inch intervals; drizzle with remaining 2 Tbsp. oil, and sprinkle with salt, rosemary, and caramelized onions.
3. Bake at 425° on lowest oven rack 20 minutes or until lightly browned.
Kitchen Express: Substitute 1 (13.8-oz.) can refrigerated pizza crust dough for bakery pizza dough. Reduce salt to 3/4 tsp. Reduce bake time to 10 minutes or until lightly browned.