Sweet and Sour Sauce

1/2 c cold water
1/2 c brown sugar
1/4 c vinegar
1/4 c ketchup
1/2 c water
1 Tbsp cornstarch

Mix together the 1/2 c of cold water, sugar, vinegar and ketchup. Mix 1/2 c water and cornstarch. Add this to the first liquid and boil until thickened.