In a large bowl, combine ground beef, ground chicken, finely chopped onion, minced garlic, chopped parsley, 1/2 teaspoon salt, 1/4 teaspoon black pepper, ground ginger, and the egg. Mix well until fully combined.
Gradually add the flour to the meat mixture and mix until a soft dough forms. If the mixture is too sticky, add a little more flour, one tablespoon at a time.
Form the dough into small dumplings about 1 inch in diameter and set aside on a plate.
In a large pot, heat olive oil over medium heat. Add diced onion, sliced carrots, and sliced celery. Sauté for 5-7 minutes until vegetables are softened.
Add minced garlic and dried thyme to the pot and cook for 1 minute until fragrant.
Pour in the chicken broth and bring the mixture to a boil.
Once boiling, carefully drop the dumplings into the broth one by one. Reduce heat to a simmer.
Cover the pot and simmer for 25 minutes, stirring occasionally to prevent dumplings from sticking to the bottom.
Add baby spinach leaves to the soup and cook for an additional 5 minutes until the spinach is wilted and dumplings are cooked through.
Taste the soup and adjust seasoning with 1/2 teaspoon salt and 1/4 teaspoon black pepper if needed.
Ladle the soup into bowls and serve hot.