Mix all the marinade ingredients together in a large bowl. Place chicken in bowl and make sure it is coated. Cover and place in the fridge for at least an hour (over night is best).
When the chicken is done marinading start the sauce by melting the butter in a medium saucepan. Add in brown sugar until completely blended.
Add in pineapple, mango, vinegar, Garlic, cayenne, salt and pepper. Bring to a boil, reduce heat and allow to simmer for about 15 minutes.
Remove the fruit chunks from the pan and mash them down, straining out the excess juice. Set the fruit aside and pour the juice back into the pan. Mix cornstarch into the water and slowly stir into the sauce. Allow to continue to cook while stirring until it reaches your desired thickness.
Heat your oil to 350˚. In a large bowl whisk together all the ingredients for the breading. Remove the chicken from the marinade and allow excess to drop off. Place chicken in breading mixture and toss until completely coated.
Place coated chicken into heated oil and allow to fry for anywhere form 7 to 10 minutes, making sure the chicken cooks all the way through.
Take about a 1/2 cup of the crushed fruit from earlier and mix it back into the sauce. Pour sauce over chicken and serve.