Start by heating olive oil in a skillet over medium heat. Add the Italian sausage, breaking it into small crumbles as it cooks. Cook until the sausage is no longer pink and slightly browned. This step is crucial as it locks in the flavors and ensures a rich base for your soup. Once cooked, drain any excess fat, if needed.
Next, transfer the cooked sausage to your crockpot. Add the diced tomatoes with juices, chicken broth, minced garlic, chopped onion, dried basil, and oregano. Stir well, ensuring the ingredients are evenly distributed. Season with salt and pepper to taste.
Set your crockpot to low and cook for 4-5 hours, or choose the high setting for 2-3 hours. During this time, the flavors will mingle, allowing the soup to develop its rich taste.
About 30 minutes before the cooking time ends, stir in the cheese tortellini and fresh spinach. If you're using frozen tortellini, you may need to adjust cooking time slightly to ensure they're heated through. The spinach will wilt beautifully, adding both flavor and nutrition.
To elevate the soup, pour in the heavy cream or half-and-half 15 minutes before serving. Mix thoroughly, bringing everything together. Allow the soup to warm through, but avoid letting it boil, as this can alter the texture of the cream.
Ladle the soup into bowls and sprinkle with freshly grated Parmesan cheese and chopped basil. Serve it with crusty bread or a side salad for a complete meal.