Heat 1 tablespoon olive oil in a medium saucepan over medium heat. Add sausage and cook until browned, about 3-5 minutes, making sure to crumble the sausage as it cooks; drain excess fat and set aside.

Add garlic and onion, and cook, stirring occasionally, until translucent, about 3-4 minutes.

Stir in tomatoes, Italian seasoning and red pepper flakes, if using; season with salt and pepper, to taste. Bring to a boil; reduce heat and simmer until thickened, about 10-12 minutes; set aside.

Preheat oven to 450 degrees F. Move oven rack to the lowest position.

Lightly coat a 10-inch cast iron skillet with remaining 1 tablespoon olive oil; sprinkle skillet with cornmeal.

Working on a surface that has been sprinkled with cornmeal, roll out the pizza into a 12-inch-diameter round. Transfer to prepared cast iron skillet, carefully pressing the dough into the bottom and up the sides of the skillet.

Top with mozzarella, sausage and tomato mixture in an even layer; sprinkle with Parmesan.

Place into oven and bake until the crust is golden brown, about 20-24 minutes. Let stand 5 minutes.

Serve immediately, garnished with basil, if desired.