01 - Place chicken, diced onion, sliced carrots, sliced celery, minced garlic, dried thyme, dried parsley, bay leaf, salt, and black pepper into the slow cooker insert. Pour the chicken broth over the ingredients and stir to combine evenly.
02 - Secure the lid on the slow cooker and cook on the 'low' setting for 5 hours, or until the chicken is exceptionally tender and easily shreddable.
03 - Carefully remove the cooked chicken from the slow cooker. Using two forks, shred the chicken into bite-sized pieces, then promptly return the shredded chicken to the slow cooker. Discard the bay leaf.
04 - Stir the heavy cream and 2 tablespoons of unsalted butter into the slow cooker mixture until fully incorporated.
05 - In a separate mixing bowl, whisk together the all-purpose flour, baking powder, and salt. Incorporate the melted butter and whole milk, stirring until a cohesive dough forms. Gently fold in the fresh parsley, if using. Avoid overmixing to ensure tender dumplings.
06 - Drop rounded tablespoonfuls of the dumpling dough directly onto the surface of the simmering stew in the slow cooker. Ensure the dumplings are spaced slightly apart to allow for even cooking and expansion.
07 - Replace the lid on the slow cooker and switch to the 'high' setting. Cook for an additional 1 hour, or until the dumplings are puffed, fully cooked through, and tender.
08 - Before serving, taste the stew and adjust salt and pepper as necessary to achieve desired flavor balance.