In a mixing bowl, stir together the pork shoulder and pancetta with your hands until well mixed. Add pepper, salt and white wine and mix until well blended, again with your hands. You must move quickly here or your body temperature could change the texture of the fat. Set up the sausage stuffer and place the casing over the funnel feeder. If you do not have a sausage stuffer, form the sausage into 1/4 pound logs by hand and be careful handling them. Stuff the sausage into the casings, twisting every 3 1/2 to 4 inches so that each sausage is about 4 ounces, and form 22 to 25 sausages. Prick them all over with a needle and set aside in a cool place.
In a 12 to 14-inch frying pan, heat the oil over medium heat until smoking. Add the onions, peppers, chili flakes and oregano and cook 8 to 10 minutes, until softened. Add the tomato paste and cook 15 to 18 minutes, until paste turns a darker color. Add the red wine and simmer 10 minutes. Remove from the heat and allow to cool.
To finish the dish, place a 14 to 16-inch skillet over medium heat and place the sausages in the pan. Cook for 7 to 9 minutes, until dark golden brown on the bottom, moving sausages carefully and frequently. Turn the sausages and add the pepper mixture. Bring to a boil, lower the heat and simmer for 25 to30 minutes, augmenting the pan with water, 1/4 cup at a time to keep the liquidity near that of a ragu. Remove from heat, divide equally among 6 warmed dinner plates, and serve immediately.
Recipe copyright 2000, Mario Batali. All Rights Reserved