How to Make It
Preheat oven to 550°F (or as hot as your oven will go). Heat a 12-inch cast iron skillet on stovetop over medium- high. Add sausage; cook, stirring occasionally to break into large pieces, until browned, 6 to 8 minutes. Transfer to a plate lined with paper towels.
Wipe skillet clean, and return to medium-high. Sprinkle skillet lightly with cornmeal, and carefully place dough round in skillet, pressing 1/2-inch up sides. Brush with oil; sprinkle with salt. Cook dough over medium-high until it just begins to bubble, about 1 to 2 minutes. Spread pizza sauce over crust. Top with mozzarella, sausage, pepperoni, and onion.
Bake in preheated oven until golden brown and starting to char, 10 to 12 minutes. Let pizza stand 5 minutes; transfer to a cutting board. Garnish with basil, if desired.