If using cardoons: cut the cardoon stalks into 1/2-inch pieces and place in a large bowl. Cover with water and add the juice of 1 lemon. Set aside to soak for about 3 hours. Drain the cardoon pieces and place in a medium saucepan. Cover with cold water, to which 1 tablespoon of salt has been added, then add the juice of 1 lemon and the flour. Bring to a boil and cook gently over medium-high heat, about 15 to 20 minutes, or until the cardoon pieces are very tender. Drain and squeeze dry, then set aside.
If using artichokes: trim the leaves from the artichokes, remove the choke, and peel the stem. Drop each into acidulated water as finished. Drain the hearts and place in a medium saucepan. Cover with cold water, to which 1 tablespoon of salt has been added, then add then add the juice of 1 lemon and the flour. Bring to a boil and cook gently over medium-high heat, about 10 to 15 minutes, or until the hearts are very tender. Drain and pat dry, then set aside.
In a large bowl, combine the pork, 3 eggs, 1 cup cheese, and salt and pepper, to taste, and mix well. Roll the mixture into small balls, no more than 3/4-inch in diameter. Set aside.
Beat the remaining 5 eggs into the cardoons, then stir in the remaining 1 3/4 cups cheese. Pour into a saucepan, place over low heat and cook until it starts to thicken.
Heat the olive oil in a soup pot, over medium heat. Add the meatballs, in batches of 6 or 7, and cook until they are light golden brown. Transfer to a plate as they are cooked. Add the onions to the pan and scrape up the brown bits with a wooden spoon while stirring the onions. Pour in the stock and bring to a boil. Lower the heat and add the meatballs and the reserved cardoon/egg mixture. Cover and simmer 10 minutes, or until the meatballs are cooked through. Serve hot.
Brown Chicken Stock:
In a large, heavy-bottomed saucepan, heat the oil over high heat until smoking. Add all the chicken parts and brown all over, stirring to avoid burning. Remove the chicken and reserve. Add the carrots, onions, and celery to the pot and cook until soft and browned. Return the chicken to the pot and add 6 quarts of water, the tomato paste, peppercorns, and parsley. Stir with a wooden spoon to dislodge the browned chicken and vegetables bits from the bottom of the pan. Bring almost to a boil, then reduce heat and cook at a low simmer until reduced by half, about 2 hours, occasionally skimming excess fat. Remove from heat, strain, and press on the solids with the bottom of a ladle to extract out all liquids. Stir the stock to facilitate cooling and set aside. Refrigerate stock in small containers for up to a week or freeze for up to a month.
Yield: 3 quarts