Rosemary Potato and Caramelized Onion Pizza

Remove the dough from the refrigerator 30 minutes before shaping. Position an oven rack in the lower third and preheat the oven to 475°F. Scrub the potatoes and slice them 1/8 inch thick. Peel, halve, and slice the onion about 1/8 inch thick. Finely chop the rosemary and grate the mozzarella.

Heat 1 tablespoon olive oil in the skillet over medium-high heat. Add the onion and 1/4 teaspoon salt and cook uncovered for 3 minutes, stirring often. Add 2 tablespoons water, cover, and cook for 3 minutes. Uncover and continue cooking over medium-high heat for 8 to 9 minutes, stirring frequently and scraping up the browned bits. Reduce the heat to medium if the onion begins to scorch. Do not proceed until the onion is uniformly deep golden, very soft, and jammy. Remove from the heat.

While the onion cooks, place the potatoes and remaining 1 tablespoon water in the microwave-safe bowl. Cover and microwave on high for 3 minutes. Open the bowl away from your face and stir carefully, then microwave for 1 to 2 minutes, until the slices are flexible but still intact. Drain and pat thoroughly dry. Toss with 1 tablespoon olive oil, 1/2 teaspoon salt, the black pepper, and 2 teaspoons rosemary.

Coat the rimmed baking sheet with the remaining 1 tablespoon olive oil. Lightly flour the work surface and your hands. Press the dough into a thick disk, then lift and rotate it over the backs of your hands to stretch it gradually. Place it on the prepared baking sheet and press it into a 14-by-10-inch rectangle, leaving a slightly thicker 1/2-inch border. If the dough springs back, let it rest for 5 minutes, then finish pressing it into shape.

Scatter 6 ounces mozzarella evenly over the dough, keeping the raised border uncovered. Distribute the caramelized onion in small clusters. Arrange the potatoes in slightly overlapping rows so some onion remains visible, then scatter the remaining 2 ounces mozzarella over the top.

Wearing oven mitts, remove the baking sheet and place it on a heat-safe surface. Sprinkle the pizza with the remaining 1 teaspoon rosemary. Cool for 5 minutes, transfer carefully to a cutting board with a large spatula, and cut into 8 slices.