01 - Combine chicken thighs, diced onion, sliced carrots, celery, minced garlic, chicken broth, thyme, parsley, bay leaf, salt, and pepper in the slow cooker. Stir thoroughly to distribute seasonings evenly.
02 - Cover and cook on low setting for 5 hours until chicken is tender and fully cooked through.
03 - Remove cooked chicken from the slow cooker and shred using two forks. Return shredded chicken to the pot.
04 - Melt 2 tablespoons butter in a small saucepan over medium heat. Whisk in 3 tablespoons flour and cook for 1 minute. Gradually whisk in 1 cup milk and ¼ cup cream until smooth and slightly thickened. Pour this mixture into the slow cooker and stir well to incorporate.
05 - Combine flour, baking powder, and salt in a mixing bowl. Cut in cold butter until mixture resembles coarse crumbs. Stir in milk and parsley until just combined. Do not overmix.
06 - Drop spoonfuls of dumpling batter (approximately 2 tablespoons each) onto the surface of the stew. Cover and cook on high setting for 1 hour until dumplings are cooked through and fluffy.
07 - Remove and discard bay leaf. Ladle hot stew into serving bowls and serve immediately.