In a slow cooker, combine the diced onion, minced garlic, Italian seasoning, salt, black pepper, and crushed red pepper flakes (if using).
Pour in the chicken stock and stir everything together.
Add the chicken breasts to the slow cooker.
Sprinkle the chopped sundried tomatoes over the top.
Cover and cook on low for 6-8 hours or on high for 3-4 hours until the chicken is cooked through and tender.
Remove the chicken breasts from the slow cooker and shred them using two forks. Return the shredded chicken to the slow cooker.
In a separate bowl, whisk together the heavy cream and cornstarch until smooth. Pour this mixture into the slow cooker and stir well to combine.
Cover and continue cooking on high for an additional 30 minutes.
Meanwhile, cook the lasagna noodles according to package instructions. Drain and set aside.
Stir in the fresh spinach until wilted.
Just before serving, add the cooked lasagna noodles to the slow cooker and stir gently to incorporate.
Serve the Slow Cooker White Lasagna Soup hot, topped with shredded Parmesan cheese and fresh parsley for garnish. Enjoy!
Notes
If you prefer a milder flavor, you can omit the crushed red pepper flakes or adjust the amount according to your taste.
Make sure to use boneless, skinless chicken breasts for easier shredding.
For a richer and creamier soup, use heavy cream. However, if you prefer a lighter option, you can substitute it with half-and-half or whole milk.
The cornstarch helps thicken the soup. If you want a thicker consistency, you can increase the amount of cornstarch slightly.
Remember to cook the lasagna noodles separately and add them just before serving to prevent them from becoming mushy.
Leftover soup can be stored in an airtight container in the refrigerator for up to 3-4 days. Reheat gently on the stovetop or in the microwave before serving.
Garnish the soup with shredded Parmesan cheese and fresh parsley right before serving to add extra flavor and freshness.