3/4 cup diced day- old, crustless bread
1/4 cup whole milk
1 1/2 cups freshly grated Parmigiano- Reggiano (about 6 ounces), plus a wedge of Parmigiano-Reggiano for grating
1/2 large yellow Spanish onion, minced (about 1 cup)
2/3 cup finely chopped fresh Italian parsley leaves
2 extra- large eggs
4 large garlic cloves, minced
2 to 3 teaspoons pure ground red pepper flakes, plus more to taste
2 teaspoons kosher salt
1 teaspoon freshly ground black pepper
1 pound ground pork (preferably pork butt)
1 pound ground veal
6 1/2 ounces pancetta, finely chopped or minced in a miniature food processor
All-purpose flour, for dredging (about 2 cups)
1/4 cup extra- virgin olive oil, plus more as needed
1 quart Passata de Pomodoro (recipe follows) or tomato sauce
1 quart chicken stock
3 dried bay leaves
3 dried arbol chiles
Buttered semolina toast, for serving (optional)

Passata di Pomodoro
2 28-ounce cans whole peeled plum tomatoes, including their juices (such as San Marzano)
1/4 cup extra virgin olive oil
1 tablespoon sugar, plus more as desired
1 scant tablespoon kosher salt
1 heaping teaspoon freshly ground black pepper