1. Start by boiling a pot of salted water. Add the cheese tortellini and cook until al dente. Drain and set aside.
2. In a large pot, heat olive oil and butter over medium heat. Add onions, carrots, and celery, sautéing until tender.
3. Add minced garlic to the pot and cook until fragrant, being careful not to burn it.
4. Sprinkle flour over the sautéed vegetables, stirring continuously to coat them evenly. Cook for a minute to eliminate the raw flour taste.
5. Gradually add chicken broth while stirring to avoid lumps. Introduce dried thyme, oregano, Italian seasoning, salt, and pepper to season the mixture.
6. Bring the soup to a gentle simmer to unfold the flavors.
7. Reduce heat and stir in heavy cream and whole milk. Simmer while maintaining a creamy but not boiling liquid.
8. Add shredded chicken and frozen sweet corn. Stir and continue simmering until the chicken is heated through.
9. Add the cooked tortellini to the soup pot, allowing it to heat through without boiling.
10. Stir in grated Parmesan cheese and optional spinach or garnishes like fresh herbs. Adjust the seasoning as needed.
11. Cook just until the cheese melts and the soup reaches your desired consistency.
12. Serve warm and enjoy the comforting, creamy flavors of your Creamy Chicken Tortellini Soup!