Heat the olive oil in a large Dutch oven or soup pot over medium-high heat. Add the ground Italian sausage and cook until browned, breaking it apart with a wooden spoon (about 5-7 minutes).

Add the diced onion to the pot with the sausage and sauté for 3 minutes until softened. Stir in the minced garlic and Italian seasoning, cooking for 1 minute until fragrant.

Pour in the crushed tomatoes and chicken broth. Bring the soup to a gentle boil, then reduce the heat to low, cover, and let it simmer for 10 minutes to allow the flavors to develop.

Stir in the heavy whipping cream and the refrigerated cheese tortellini. Simmer uncovered for 3-5 minutes, or until the tortellini are tender and floating to the top.

Remove the pot from the heat and stir in the fresh baby spinach. Let it sit for 1 minute until the spinach is wilted.

Ladle the soup into bowls, garnish generously with freshly grated parmesan cheese, and serve immediately with crusty garlic bread.