Add the chicken thighs, carrots, celery, onion, garlic, diced tomatoes, cannellini beans, chicken broth, Italian seasoning, dried basil, and red pepper flakes to the slow cooker. Stir so the seasonings are evenly distributed.

Cover and cook on Low for 6-8 hours, until the chicken is cooked through and the broth looks richly infused with tomato. (Or cook on High for 3-4 hours.)

Remove the chicken, shred it, and return the shredded chicken to the pot. The soup should look thick and flavorful after the chicken goes back in.

Add the ditalini (or egg noodles) and cook on High for 20-30 minutes, until the noodles are tender and the broth stays active with small bubbles. Stir occasionally to prevent sticking.

Stir in the fresh spinach and cook for 5 minutes, until it wilts and turns bright green. You should see the spinach evenly dispersed throughout the soup.

Season with salt and black pepper to taste, then ladle into bowls. Top each serving with parmesan shavings and fresh basil.