Prepare the dough: In a large mixing bowl, combine the "00" flour and Manitoba flour. Crumble in the fresh brewer's yeast and add the sugar. Pour in half of the lukewarm water and begin incorporating the ingredients using a dough scraper or flat pastry cutter.
Knead the dough: Add the fine salt and the remaining water, continuing to mix with the dough scraper. Drizzle in the extra virgin olive oil and begin kneading by hand. Once the dough comes together, turn it out onto a flat work surface and knead vigorously for a few minutes until smooth, elastic, and homogeneous.
Portion and shape the dough balls: Shape the dough into a long log and cut it into 10 equal pieces (about 80 g / 3 oz each). To form each ball, flatten a portion of dough on the counter, fold the outer edges inward toward the center, then flip it over. Cup your hand gently over the dough and roll it against the surface in a circular motion to create a tight, smooth ball.
First rise: Arrange the dough balls on a tray, spaced well apart. Cover them with a clean kitchen towel and let them rise in a warm spot for about 1.5 hours, or until doubled in size.
Prepare the filling: While the dough is rising, cut the mozzarella into small cubes and place it in a fine-mesh strainer to drain off excess whey. In a separate bowl, season the tomato passata with salt, dried oregano, and a drizzle of extra virgin olive oil. Stir well to combine.
Assemble the panzerotti: Take one risen dough ball at a time and place it on a lightly floured work surface. Gently press it flat and roll it out with a rolling pin into a round disk approximately 2 mm (1/16 inch) thick. Spoon a tablespoon of tomato sauce into the center, followed by a portion of drained mozzarella.
Seal the edges: Fold the dough over the filling to form a half-moon (crescent) shape. Press firmly along the edges with your fingertips to expel any trapped air and seal the dough tightly. Trim the excess border using a pastry wheel or sharp knife to ensure a clean, leak-proof seal.
Fry and serve: Heat plenty of vegetable oil in a deep saucepan or Dutch oven to 325°F (170°C). Fry the panzerotti in small batches (1 or 2 at a time) to prevent the oil temperature from dropping. Turn them frequently to ensure even cooking and puffing. Once golden-brown on both sides, remove with a slotted spoon and drain on paper towels. Serve immediately while piping hot.
