Finely dice the white onion into 1/4-inch pieces and mince the garlic cloves. In your slow cooker, combine the diced onion, minced garlic, Italian seasoning, salt, black pepper, and red pepper flakes. Add the chicken stock and stir well to distribute the seasonings evenly. Place the chicken breasts directly into the seasoned stock, then scatter the chopped sundried tomatoes around them. Cover and set the slow cooker to low heat for 6-8 hours (or high for 3-4 hours if you're short on time).

Once the slow cooker has finished cooking and the chicken is very tender, carefully remove the chicken breasts and shred them using two forks or your hands (it should pull apart easily). Return the shredded chicken to the pot. In a small bowl, whisk together the cream and cornstarch until smooth and completely combined—this prevents lumps in your soup. Pour the cream mixture into the slow cooker and stir thoroughly to incorporate it evenly throughout the broth. Turn the heat to high and cook uncovered for 30 minutes, stirring occasionally, to thicken the soup and meld the flavors.

While the soup is thickening in the slow cooker, bring a large pot of salted water to a boil. Add the lasagna noodles broken into 1-inch to 2-inch bite-sized pieces and cook according to package directions until al dente (usually 8-10 minutes). I prefer to cook the pasta separately rather than directly in the slow cooker because it prevents the noodles from becoming mushy and gives you better control over the final texture. Drain the pasta in a colander and set aside.

After the 30-minute thickening period, stir the fresh spinach into the slow cooker. The residual heat will quickly wilt it into the creamy broth within 2-3 minutes of stirring—you'll see it soften and darken as it incorporates. Once the spinach has wilted, add the cooked pasta from Step 3 and gently fold everything together until evenly distributed throughout the soup.

Ladle the soup into bowls and top each serving with shredded Parmesan cheese and fresh parsley. I like using Kraft Parmesan for that classic salty finish it brings to the dish—it complements the creamy soup beautifully. Serve immediately while hot and enjoy the comforting lasagna flavors in soup form.