In a large pot, heat olive oil over medium heat and add onions. Cook 2-3 minutes and add garlic. Add sausage and brown.
Pour in tomatoes and chicken broth. Bring to a simmer and add tortellini. Cook tortellini according to package instructions. Just before tortellini is finished, add spinach and cover. When spinach is wilted, add a generous amount of pepper (to taste) and remove from heat. ***This recipe didn't need salt because of the salt in the chicken broth and sausage. If too salty, add water.
Ladle soup into bowls and sprinkle with parmesan cheese. Serve.