In a large Dutch oven or large soup pot, cook onion and sausage until meat is cooked through. Add the garlic and cook for another minute. Pour in broth, water, and diced tomatoes and bring to a boil.

Add tortellini and cook for about 3-4 minutes. Reduce heat and add spinach, basil, pepper and red pepper flakes. Cook for another minute, just until spinach has wilted. Remove from heat and serve.

** If you are planning to save some of the soup in jars to eat on another day you can cook the tortellini in a seperate pot and keep them in a tupperware container. Add them to your serving of soup as you reheat it.This will prevent the tortellini from getting too soft and also from soaking up too much broth.