Dice the celery and carrots into uniform 1/4-inch pieces—this consistent size ensures they cook evenly in the slow cooker. Dice the onion into similar-sized pieces. Combine the diced vegetables with the dried parsley, garlic, thyme, salt, and pepper in a small bowl. I like to mix the aromatics and seasonings together first so they distribute evenly throughout the broth and don't clump up when added to the cooker.

Pour the chicken broth into your slow cooker and add the chicken breasts whole—they'll be easier to shred later if they stay intact during cooking. Add the seasoned vegetable mixture from Step 1, stirring gently to distribute the aromatics and vegetables throughout the liquid. Set the slow cooker to low and cook for 6-7 hours (or high for 3-4 hours if you're short on time). The long, gentle cooking will develop deep, savory flavors as the chicken becomes tender and infuses the broth.

Once the cooking time is complete, carefully remove the chicken breasts from the slow cooker and place them on a cutting board to cool slightly. Using two forks or your hands, shred the chicken into bite-sized pieces and set aside. While the chicken cools, whisk together the heavy cream, corn starch, and ground nutmeg in a small bowl until the corn starch is fully dissolved—this slurry will thicken the soup beautifully and give it a luxurious texture without using flour.

Return the shredded chicken from Step 3 to the slow cooker, then pour in the cream mixture, stirring well to combine. Add the gnocchi and increase the slow cooker to high heat. Cook for 1 hour, stirring occasionally to prevent the gnocchi from sticking to the bottom and to help the thickening agent work evenly throughout the soup. I find that stirring every 15-20 minutes gives you the best results and ensures the gnocchi cooks through without breaking apart.

Stir in the spinach and Parmesan cheese until the spinach is fully wilted and the cheese is melted throughout the soup—this should take just 2-3 minutes on high heat. Taste the soup and adjust the seasoning with additional salt and pepper if needed. Ladle into bowls and serve immediately while hot and creamy.