Dice the onion into 1/2-inch pieces, mince the garlic cloves, and chop the sun-dried tomatoes into 1/4-inch pieces. Cut the chicken breast into 1-inch chunks and set aside. In a large pot over medium heat, melt the butter until it foams, then add the diced onion and cook for 3-4 minutes, stirring occasionally, until softened and translucent. This builds the flavor foundation for your soup.

Add the minced garlic, Italian seasoning, salt, pepper, and chili flakes to the softened onions. Stir constantly for about 1 minute until fragrant—this blooms the spices and releases their essential oils, creating deeper flavor in your final soup. Don't skip this step as it's crucial for building layers of taste.

Pour in the chicken broth and add the chicken chunks and chopped sun-dried tomatoes. Bring to a gentle simmer, then cover the pot and cook for 12-15 minutes until the chicken reaches an internal temperature of 165°F. While the chicken simmers, start boiling pasta in a separate pot of salted water according to package directions—I like using campanelle or fusilli as they hold the creamy sauce beautifully.

Once the chicken is fully cooked, carefully remove it from the soup using a slotted spoon and set it aside on a cutting board. In a small bowl, whisk together the half-and-half and cornstarch until completely smooth with no lumps—this mixture is called a liaison and will thicken your soup without making it gummy. Pour the liaison into the simmering broth while stirring constantly, then cook for 1-2 minutes until slightly thickened. The soup should coat the back of a spoon lightly.

Shred the cooked chicken into bite-sized pieces and return it to the pot. Drain the cooked pasta and add it to the soup along with the fresh spinach and nutritional yeast. Stir gently for about 1-2 minutes until the spinach wilts and everything is heated through. Taste and adjust seasonings if needed—the soup should be creamy and comforting with tender chicken and pasta throughout.

Ladle the white lasagna soup into bowls and top each serving with a combination of ricotta cheese, grated Parmesan cheese, and shredded mozzarella cheese. For the best presentation and melting, I like to spoon a dollop of ricotta directly into the center, then sprinkle the harder cheeses around it. The warm soup will soften the cheeses into a luxurious, creamy finish.