Fill a large Dutch oven slightly more than half full with water and add the beef bouillon cubes to create your broth base.

Prepare your vegetables by cubing the potatoes, chopping the carrots, onion, and celery, and halving the corn ears.

Add the prepared potatoes, carrots, onion, celery, corn, and stewed tomatoes to the pot. Bring everything to a boil.

While the broth is heating, prepare the meatballs. In a large mixing bowl, combine the ground beef, cooked rice, corn flakes, chopped cilantro, and egg.

Mix the meatball ingredients thoroughly with your hands until well combined.

Form the mixture into golf ball-sized meatballs.

Once the broth is boiling, carefully drop the meatballs into the pot one by one.

Allow the meatballs to cook in the simmering broth for about 25 minutes, during which they'll become tender and flavor the soup.

During the final 5 minutes of cooking, add the chopped zucchini and cabbage to the pot.

Season the soup with salt and pepper to taste.

Serve hot, ensuring each bowl contains at least one or two meatballs and plenty of vegetables and broth.