Makes about 2 dozen medium meatballs
1 large onion, cut into chunks 3 garlic cloves 1 pound ground pork or chicken 1 pound ground beef or veal 2 large eggs 1/2 cup freshly grated Parmigiano-Reggiano, plus more for serving 1/2 cup freshly grated Pecorino Romano 1-1/2 cups unseasoned fresh bread crumbs 1/4 cup chopped fresh Italian parsley Sea salt and freshly ground black pepper
1. In a food processor, combine onion, garlic, and 1 cup water. Puree until very smooth. In alarge mixing bowl, combine the ground meat, eggs, Parmigiano-Reggiano, Pecorino Romano, bread crumbs, parsley, salt and pepper. Add the onion puree and, with your hands, mix until just combined. Form 1 small meatball and fry, just to taste for seasoning, and adjust if necessary.
2. Wet your hands and form the meat mixture into 24 meatballs. Don't overwork the mixture - the meatballs should be light and soft, not spongy and tough. Put the meatballs on a rimmed sheet pan and refrigerate 30 minutes to firm them up.
3. Preheat oven to 350 degrees F. When ready to fry, in a large skillet over medium heat, heat enough oil (expeller-pressed oils recommended) to come one-third of the way up the sides of the meatballs. Fry the meatballs, in batches, until browned all over, about 6 minutes per batch. Drain and place on a rimmed sheet pan. When all the meatballs are browned, place in the oven and bake until cooked through, about 15 minutes. (The browned meatballs can also be finished by simmering in marinara or other tomato sauce for 30 minutes.) Serve with heaps of shredded Parmigiano-Reggiano.
Adapted from recipe in "Food & Wine" magazine