Sprinkle the yeast over the warm water in a measuring cup and let it activate for about 5 minutes.

In a bowl, combine 3 cups of flour, Parmesan cheese, baking powder, salt, and sugar. Stir well together.

Incorporate 2 tablespoons of olive oil into the flour mixture, then add the yeast water and mix until a dough begins to form.

Dust a work surface with the remaining flour and knead the dough for around 10 minutes until smooth, then shape it into a ball.

Coat a bowl with 1 tablespoon of olive oil, place the dough inside, cover it, and allow it to rise in a warm area until it doubles in size, about an hour.

Once the dough has risen, prepare your surface again for rolling, cut the dough into 2-inch pieces, and roll them into balls.

Flatten each ball into a circle about ½-inch thick and 5 inches wide, ensuring the center is slightly thicker.

In the center of each circle, place 1 tablespoon of tomato sauce, sprinkle in 2 tablespoons of mozzarella, and top with 1 tablespoon of chopped basil. Add a pinch of salt as well.

Fold the dough over to form a pocket and press the edges together to seal. Repeat for all dough portions.

Heat 2 inches of oil in a deep pot until it reaches 365°F (185°C).

Cook the calzones in batches, frying each for approximately 3 minutes on each side until golden brown. Drain on paper towels afterward.

Serve the calzones hot, with the remaining tomato sauce for dipping and a garnish of fresh parsley.