Mound the 00 flour and semolina on a clean work surface or in a large bowl and make a well in the center. Crack in the eggs, add the salt and olive oil, and beat with a fork, gradually pulling in flour from the edges.

Knead the dough by hand for 8 to 10 minutes until it turns smooth and springs back when poked. Wrap tightly in plastic and let it rest at room temperature for 30 minutes.

Divide the rested dough into 4 pieces. Roll each piece through a pasta machine, or by hand with a rolling pin, down to about 2 mm thick.

Cut the sheets into rough diamond or rectangle shapes roughly 5 cm across, the ragged edges are the point, not a flaw. Dust with semolina and spread on a floured tray while you make the sauce.

Heat the olive oil in a 12-inch / 30 cm skillet over medium heat. Add the pancetta and cook for 5 to 6 minutes, stirring occasionally, until the edges turn golden and the fat has rendered.

Add the onion and garlic to the same skillet. Cook for 4 to 5 minutes, stirring often, until the onion turns soft and translucent.

Pour in the white wine and let it bubble for 1 to 2 minutes until the sharp smell cooks off.

Stir in the tomato passata and chili flakes. Simmer uncovered for 15 to 18 minutes, stirring now and then, until the sauce thickens enough to coat the back of a spoon.

Bring a 6-quart / 5.7 L pot of well-salted water to a rolling boil. Drop in the fregnacce and cook for 2 to 3 minutes, just until they float to the surface and taste tender with a slight bite.

Scoop out about 120 ml / 1/2 cup of the pasta water, then drain the fregnacce in a colander.

Tip the pasta straight into the skillet with the sauce. Toss over low heat for 1 to 2 minutes, adding a splash of the reserved pasta water if the sauce looks tight, until every piece is coated.

Remove from the heat and stir in half the pecorino. Plate immediately, finishing with more pecorino and a scatter of parsley.