In a large soup pot, cook the Italian sausage over medium heat, breaking it up as it cooks until fully browned. Transfer to a paper towel-lined plate to absorb excess fat.

With the sausage set aside, add the chopped onion and celery to the pot. Sauté for about 4-5 minutes until they become tender and fragrant. Then stir in the minced garlic and let that cook for an additional minute.

Next, sprinkle the flour over the softened vegetables, stirring continuously for about a minute. Gradually pour in the chicken broth while stirring, ensuring you prevent any lumps from forming.

Add the diced tomatoes (juices included) and Italian seasoning, bringing everything back to a gentle boil. Return the sausage to the pot and let it simmer.

Gently lower the heat and stir in the tortellini, cooking for about 5 minutes until they are cooked through and soft.

Stir in the heavy cream and fresh spinach, allowing the spinach to wilt for 2-3 minutes. Finally, season it with salt and pepper before serving hot.