Creating Cozy Upside-Down Deep-Dish Skillet Pizza is straightforward if you follow these steps:

1. Preheat Oven: Preheat your oven to 425°F (220°C).
2. Prepare the Skillet: Heat a large cast-iron skillet over medium heat. Add olive oil and swirl to coat the bottom.
3. Cook Vegetables: Sauté the diced onion and bell pepper in the skillet for about 3-4 minutes until softened. Remove and set aside.
4. Roll Out Dough: On a floured surface, roll out the pizza dough into a circle large enough to cover the skillet.
5. Layer Cheese: Sprinkle half of the shredded mozzarella cheese evenly on the bottom of the skillet.
6. Add Toppings: Layer the sautéed vegetables, pepperoni, and any additional toppings over the cheese.
7. Add Sauce: Pour the pizza sauce evenly over the toppings.
8. Add Remaining Cheese: Top with the remaining mozzarella cheese for that gooey texture.
9. Cover with Dough: Carefully place the rolled-out pizza dough over the cheese and toppings, tucking the edges in.
10. Bake: Transfer the skillet to the preheated oven and bake for 30-35 minutes, or until the crust is golden brown.
11. Cool and Flip: Remove from the oven and let it cool for a few minutes. Carefully flip the skillet onto a large serving plate to reveal the pizza.
12. Garnish: Sprinkle with fresh basil and red pepper flakes, if desired.

Following these steps will lead you to a deliciously cozy pizza that’s sure to impress everyone at the table!