In a large pot set over medium-high, cook the sausage until browned. Transfer the cooked sausage to a paper towel lined plate; set aside.
Add onion, carrot, and celery and sauté until the vegetables are soft. Add the garlic and sauté until fragrant, stirring occasionally to prevent it from burning.
Whisk in the flour and cook for 1 minute. Gradually add in the diced tomatoes and chicken broth, whisk to combine. Continue cooking until the mixture reaches a simmer, then reduce heat to a simmer.
Add the sausage to the pot with the tortellini, spinach, and heavy cream – season to taste with salt and pepper. Simmer for 5 minutes, or until the tortellini is fully cooked.
Serve immediately with shredded parmesan, if desired.