Sweet and Sour Chicken

1 cup water
1 cup packed brown sugar
1/2 cup vinegar
2 tablespoons ketchup
1-1/2 pounds skinless chicken cut into bite sized pieces (breasts or thighs)
2 tablespoons cornstarch
2 tablespoons water

Mix first five ingredients together in crockpot, then add chicken. Stir, cover and cook on high for 3-4 hours or on low for 6-8 hours. 

Twenty minutes before serving, combine the cornstarch and water, then add and stir it into crockpot. Turn it on high (if it isn't already) and stir often for 15-20 minutes, as sauce will thicken.