In a large mixing bowl, combine the flour, salt, and sugar. In a separate bowl, dissolve the yeast in warm water and let it sit for about 5 minutes until frothy.

Pour the yeast mixture and olive oil into the flour mixture. Stir until a dough forms. Knead the dough on a floured surface for about 5-7 minutes until smooth.

Place the dough in a greased bowl, cover it with a clean kitchen towel, and let it rise in a warm place for about 1 hour or until doubled in size.

Preheat your oven to 425°F.

Once the dough has risen, punch it down and roll it out into a large circle, about 12-14 inches in diameter.

Grease a 9-inch round deep dish pizza pan or a cast-iron skillet. Place the rolled-out dough in the pan, pressing it up the sides to create a crust.

Layer the mozzarella cheese evenly on the bottom of the crust, followed by the cooked sausage, bell peppers, and mushrooms.

Pour the marinara sauce over the toppings, spreading it evenly. Sprinkle the Parmesan cheese, oregano, garlic powder, and crushed red pepper flakes on top.

Bake in the preheated oven for 30-35 minutes or until the crust is golden brown and the cheese is bubbly.

Allow the pizza to cool for about 10 minutes before slicing and serving.