1. Melt butter in a large Dutch oven over medium heat. Add diced onion, carrots, and celery. Cook for about 8 minutes until softened. Stir in garlic and cook for 1 minute more.

2. Add chicken thighs, chicken broth, and bay leaves. Bring to a boil, then reduce to a simmer. Cover and cook for 25 minutes until chicken is cooked through.

3. Remove chicken, shred with forks, then return to the pot. Season with salt and pepper. Remove bay leaves.

4. In a bowl, mix flour, baking powder, and salt. Cut in cold butter until mixture resembles crumbs. Stir in buttermilk and parsley until just combined.

5. Drop spoonfuls of dough onto the simmering soup. Cover the pot and let dumplings steam for 15 minutes without lifting the lid.

6. Once dumplings are cooked through and fluffy, ladle soup into bowls and garnish with fresh parsley if desired.