Combine all the ingredients for the meatballs (except the olive oil) in a bowl, mix well, and form into small, bite-sized balls with your hands. Heat olive oil in a soup pot and brown the meatballs on all sides. Remove meatballs and set aside.

Add onions to the pot and sauté a few minutes, until softened. To the onions, add broth, tomato paste, bay leaves, thyme, and peppercorns and bring to a boil. Reduce heat and simmer for about 5–10 minutes.

Add kale and pasta, if using, and then meatballs and simmer a few more minutes, until meatballs are cooked through and pasta is done. Season to taste with salt and pepper. Ladle into bowls and top with parsley and Parmesan cheese.