Skillet Pizza

Ingredients

• 2 tablespoons extra-virgin olive oil
• 1 pound store-bought pizza dough
• ½ cup tomato sauce
• 1 teaspoon dried oregano
• ½ teaspoon red-pepper flakes
• 2 uncooked Italian sausages, casings removed
• ½ red onion, thinly sliced
• 1½ cups shredded mozzarella cheese
• ¼ cup grated Parmesan cheese