Combine first 4 ingredients in a large saucepan; bring to a boil. Reduce heat, and simmer, uncovered, 10 minutes.
Return to a boil; add tortellini, and cook 5 minutes. Add spinach and green onions; reduce heat, and simmer 2 to 3 minutes. Ladle into individual soup bowls; sprinkle soup evenly with cheese.
Cooking Light Low-Fat, Low-Calorie Quick and Easy Cookbook