In a small bowl, combine warm water, active dry yeast, and granulated sugar. Stir gently and let sit for 5-7 minutes until frothy.
In a large mixing bowl, whisk together the flour and salt.
Add the yeast mixture and 1 tablespoon olive oil to the flour mixture. Stir with a wooden spoon until a dough forms.
Turn the dough onto a lightly floured surface and knead for about 5 minutes until smooth and elastic.
Place the dough in a lightly oiled bowl, cover with a clean kitchen towel, and let it rise in a warm place for 10 minutes.
Preheat your oven to 475°F (245°C).
Lightly oil a 10-inch cast iron skillet with olive oil.
Roll or stretch the dough into a circle slightly larger than the skillet and transfer it to the skillet, pressing it evenly to the edges.
Spread the tomato sauce evenly over the dough, leaving a small border around the edges.
Sprinkle the shredded mozzarella cheese evenly over the sauce.
Sprinkle dried oregano and crushed red pepper flakes over the cheese.
Place the skillet on the stove over medium heat and cook for 3-4 minutes until the bottom of the crust starts to brown.
Transfer the skillet to the preheated oven and bake for 12-15 minutes until the crust is golden and the cheese is bubbly and slightly browned.
Remove the skillet from the oven and let the pizza cool for 2-3 minutes.
Garnish with fresh basil leaves if desired, slice, and serve.