Ingredients

3 tablespoons plus 1 teaspoon extra-virgin olive oil

2 pounds homemade or store-bought pizza dough

2 large red onions, thinly sliced

Coarse salt and ground pepper

1 tablespoon cider vinegar

1/2 cup grated Pecorino Romano

1/2 to 1 teaspoon red-pepper flakes

Preparation

Preheat oven to 425 degrees. Coat an 11-by-17-inch rimmed baking sheet with 2 tablespoons oil. Place dough on sheet, stretching to fit (if dough springs back, let rest 20 minutes and repeat). Drizzle edges with 1 tablespoon oil. Cover with plastic wrap and let sit 15 minutes.

Meanwhile, in a large skillet, heat1 teaspoon oil over medium-high. Addonions and season with salt and pepper.Cook, stirring occasionally, until onionsare tender and golden brown in spots,12 minutes. Add vinegar and cook,stirring and scraping up browned bitswith a wooden spoon, 1 minute.

Remove plastic from dough. Withyour fingertips, poke dimples all overdough, then top with cheese, brownedonions, and red-pepper flakes. Bakeuntil golden brown around edges, about30 minutes. Let cool on sheet 5 minutes.Cut into 20 pieces and serve warmor at room temperature.