Heat 2 tablespoons olive oil in a large pot over medium-high heat. Add 1 medium yellow onion, diced, 2 medium carrots, peeled and sliced, 2 celery ribs,sliced, and 3 garlic cloves, minced. Cook until the vegetables begin to soften, about 5 minutes.
Stir in 1 tablespoon Italian seasoning, 1 teaspoon salt, ½ teaspoon black pepper, 3 cups vegetable broth, and 1 (14.5-ounce) can diced tomatoes. Bring to a boil, then reduce the heat to medium and simmer for 5 minutes, until the carrots begin to soften.
Stir in 1 (9-ounce) package refrigerated cheese tortellini and cook for about 5 minutes, stirring occasionally until the pasta is tender.
Reduce the heat to low and stir in 2 cups fresh baby spinach, 1 cup heavy cream, ½ cup shredded Parmesan cheese, and 2 tablespoons chopped basil. Cook until the spinach has wilted, about 2 minutes.
Notes
Make Ahead, Storage, & Reheating Instructions
Storage: Store leftovers in an airtight container in the fridge for 3–4 days.
Make Ahead: Cook the soup without the tortellini, then add it in when you reheat.
Reheating: Warm leftovers in a pot over medium heat until heated through. If you left out the tortellini, add it while reheating and cook for a few minutes before serving.