Heat oven to 475°F. Dust a baking sheet with cornmeal or line with parchment paper. Shape dough into a 16-inch circle, oval, or rectangle and place on the prepared baking sheet.
In a large bowl, toss potato, onion, oil, rosemary, 1⁄4 teaspoon salt, and 1⁄2 teaspoon pepper. Add cheese and toss to combine.
Scatter the mixture over dough and bake until potatoes are tender and crust is golden brown and crisp, about 15 minutes. Serve with a salad, if desired.