Add the flour to a food processor. Lightly beat the eggs in a small bowl. Pour eggs over the flour, followed by the sourdough starter. Process until the dough comes together.

Remove the dough to a lightly floured wooden surface. Cover with an upturned bowl and let rest for 3-5 minutes. Then, knead by hand for 1-2 minutes. If the dough is a bit sticky, add a sprinkle of flour to correct the texture.

Form the dough into a ball, cover tightly with plastic wrap, and rest for 1 hour at room temperature. Alternatively, ferment the dough overnight to deepen the flavor.

Melt the butter in a small skillet over medium heat. Sauté the cubed pork loin until light golden brown and cooked through.

To a food processor: Add the pork (with pan drippings), prosciutto and mortadella. Add the egg yolk, parmesan cheese and freshly grated nutmeg to taste. Process until a smooth paste forms.

Cut the dough into quarters. Working with one dough at a time: roll it into a 6-8 inch oval disc. Send the disc through the roller attachment (or pasta machine) on various settings.

Lay the pasta sheet on your work surface. Trim the edges and cut into 2×2 inch squares.

Place ~2 g (¼ tsp. rounded) of the filling into the center of each square. Fold diagonally to create a triangle. Seal the edges, pushing out any air near the filling.

Push the tip of your thumb into the bottom of the filling to create a little indent, then wrap the corner tip around your index finger to meet the other corner tip. Press gently to seal.

Set shaped tortellini on a parchment-lined sheet pan dusted with semolina flour and keep covered at all times.