Add the garlic, onion, carrot, celery, bay leaf, basil, thyme, chicken, broth and some freshly cracked pepper to a slow cooker. Stir to combine and then cook on high for 5 hours or 8 hours on low.
If you cooked on low heat, turn it to high now.
Remove the chicken from the broth and place it on a cutting board. Use two forks to shred the chicken. Return the chicken to the pot and stir in salt to the soup. Keep the slow cooker covered as much as possible during this process to retain heat and maintain the temperature.
In a medium bowl combine the flour, baking powder, salt, parsley and sugar. Mix well. Add butter in small chunks and cut it in or work it in with your hands until the mixture resembles damp sand. Add the milk and stir until a very soft paste-like mixture forms.
Remove the lid from the slow cooker and drop the dumpling batter into the soup by the heaping spoonful. Return the lid to the slow cooker and allow the dumplings to steam for 20 minutes.
After 20 minutes they should have fluffed and expanded from the heat. Although they may look moist on the outside, they will be light and fluffy on the inside. Serve hot.