<human>:  I have a question about a recipe for caramelised chicken thighs. Why do you think the recipe calls for a mixture of sugar and water?
<bot>: The sugar and water mixture is used to make a caramel. Caramel is a mixture of sugar and water that is cooked until it turns brown. The sugar and water mixture is used to make caramel because it is a very simple and easy way to make caramel.