Meatball& Zucchini Italiano

• 1 egg (beaten)
• 425 gr hamburger
• 425 gr italian-style stewed tomatoes
• 260 gr zucchini (sliced)
• 240 ml water divided
• 210 gr pasta (cooked)
• 55 gr soft bread crumbs
• 30 gr onion (finely chopped)
• 12 gr cornstarch
• 5 ml instant beef bouillon granules