Heat 2 tablespoons olive oil in a large stock pot over medium heat.
Add 1/2 cup onion and sauté until translucent and fragrant. Add 1 tablespoon of minced garlic and cook for 1-2 minutes until lightly browned.
Stir in 1/2 teaspoon of salt and dash of pepper.
Add 1 28-oz can of tomatoes and 6 cups vegetable broth and bring to a boil.
When soup is boiling, add a package of tortellini and cook according to package direction (about 5-7 minutes), until tender.
Stir in 1-2 tablespoons of lemon juice and 4 cups of baby spinach and cook until spinach is wilted.
Serve with parmesan cheese.