Word of warning: this soup would probably be just fine with either frozen meatballs from the store, or with homemade meatballs that were either fresh-not-frozen, or relatively freshly frozen. With meatballs you made yourself at some time in the past which is now just a misty dream and cannot recall for the life of you, but which you need to get out of your freezer and they can't really probably kill you, can they?... this soup is kinda meh. Or "ah-ee-ah-ee-ah-ee," which is the sound of a rubbery meatball between the molars.
Everyone ate it, though, and I seemed to be the only one who really didn't enjoy it. Such is life.
Serves four-ish, or so.
Chop up an otherwise perfectly good onion and a couple of carrots; sauté in a little olive oil 'til tender; toss in some garlic and cook just a few seconds more.
Add six cups of chicken broth, one 14-ounce can of diced tomatoes, and some chopped kale. Bring just to a boil; add some frozen/unthawed meatballs. Reduce heat and keep at a simmer--resist the urge to stir for the first few minutes, or the meatballs may fall apart--until meatballs are heated through, probably 20 minutes or so.
Add cheese tortellini according to package directions. In some cases, you may be directed to boil them; in my case, the tortellini in question needed to be Gently Simmered, not boiled, and they took only 3 minutes to be done through.
Taste; add salt; add pepper; sprinkle with grated Parmesan or Grana cheese; serve forth; good luck.