While the dough is in its final rest, preheat your oven to 475°F (245°C) with the pizza stone or baking sheet inside. The key to crispy crust is a screaming hot oven and preheated surface.
In a skillet over medium heat, cook the Italian sausage, breaking it into small crumbles as it browns. Drain on paper towels and set aside.
Roll or stretch your dough on a floured surface to your desired thickness. For a 14-inch pizza, aim for about ¼-inch thickness.
Sprinkle cornmeal or semolina on a pizza peel or the back of a baking sheet (this prevents sticking and adds a nice crunch).
Transfer your shaped dough to the peel or baking sheet. If using parchment, place the dough on a piece of parchment for the easiest transfer.
Spread the pizza sauce evenly over the dough, leaving about a ½-inch border for the crust.
Sprinkle about two-thirds of the mozzarella over the sauce.
Distribute the cooked sausage crumbles and pepperoni slices evenly over the cheese. Add bell pepper and onion if using.
Top with the remaining mozzarella and sprinkle with Parmesan cheese, dried oregano, and red pepper flakes if desired.
Carefully slide the pizza onto the preheated stone or baking sheet in the oven. If using parchment, you can slide the pizza with the parchment directly onto the stone.
Bake for 12-15 minutes until the crust is golden and the cheese is bubbly and slightly browned in spots.
Remove from the oven, garnish with fresh basil leaves, and let rest for 2 minutes before slicing. This rest time allows the cheese to set slightly, making for cleaner slices.