Take sausage out of its casing, and crumble it. Then saute sausage in a large saucepan or dutch oven over medium-high heat, breaking up large chunks with a wooden spoon.
When cooked through and browned, about 5 minutes, add 1 tablespoon olive oil, then chopped onions and carrots.
Cook for 5 minutes on medium heat, stirring frequently, until vegetables soften and brown lightly.
Add garlic and oregano and cook for an additional minute.
Add tomatoes and chicken broth, and bring to a simmer over medium-high heat.
Cover, reduce heat to medium-low, and simmer gently for 15 minutes.
Season with salt and pepper, to taste.
Add tortellini and white beans, and cook for an additional 3 minutes, until tortellini is tender.
Add spinach, and stir until wilted, about 1 minute.
Serve with parmesan cheese grated on top as a garnish.
Notes
Tortellini have different cooking times, especially if you use frozen or dried tortellini. Use the cooking instructions on your package. Soup can be refrigerated for 3-5 days or frozen for up to 3 months. However, I recommend you take out any remaining tortellini when you refrigerate or freeze. Otherwise, the tortellini will absorb more liquid and become mushy. Add new tortellini, other pasta, or rice after reheating the soup.