Prepare the chicken and the vegetables as listed in the main ingredients section. Make the marinade sauce by mixing all the sauce ingredients in a bowl. Put the chicken and vegetables into a large mixing bowl and pour the sauce on top. Mix them well. Cover the bowl with food wrap and marinate in the fridge for three hours. (You can marinate it for overnight to enhance the flavour even more.)
Put the marinated vegetables and chicken in a slow cooker. (Lay the potato and carrot in the bottom of the slow cooker followed by the chicken and onion if possible. This is to ensure that the potatoes and carrots cook properly.) Close the lid. Cook it on a low heat setting for 4 hrs.
Check the doneness of the chicken and the vegetables and mix them thoroughly but gently with a large spoon. Splash some juice over the meat and the vegetable. (The chicken should be cooked just right and potatoes and carrots well cooked but will have a firm but not mushy texture. If you prefer a mushy texture of potatoes and carrots, you might have to cook a little longer.)
Serve it in a soup bowl and garnish with spring onion and sesame seeds.