01 - Combine chicken thighs, onion, carrots, celery, garlic, thyme, parsley, black pepper, salt, and chicken broth in the slow cooker. Stir thoroughly to distribute seasonings evenly.
02 - Cover and cook on low heat for 5 hours until chicken becomes extremely tender and easily pulls apart.
03 - Remove chicken from the slow cooker and shred using two forks. Return shredded meat to the pot.
04 - Stir in heavy cream and butter pieces until fully incorporated into the broth.
05 - Whisk together flour, baking powder, and salt in a medium bowl. Add melted butter and milk, stirring until just combined. Avoid overmixing. Fold in fresh parsley if desired.
06 - Drop spoonfuls of dumpling dough (approximately 2 tablespoons each) onto the surface of the hot stew mixture.
07 - Cover and cook on high heat for 45 to 60 minutes until dumplings are puffed and completely cooked through.
08 - Taste the stew and adjust seasoning as necessary. Serve hot, garnished with additional fresh parsley.