Heat vegetable oil in a large pot over medium heat.
Add chopped onion and sauté until translucent.
Stir in minced garlic and cook for another minute.
Pour in the chicken or vegetable broth and bring to a boil.
Add sliced carrots and diced bell pepper; cook for 5 minutes.
Reduce heat to medium-low and add the frozen dumplings.
Simmer for about 8-10 minutes or until dumplings are cooked through.
Add the spinach or bok choy and cook until wilted.
Season with salt and pepper to taste.
Serve hot, garnished with chopped green onions.