1. Bring 4 cups water to a boil in a 3-qt. heavy saucepan; add tea bags. Remove from heat; cover and steep 10 minutes.
2. Discard tea bags. Stir in brown sugar and next 5 ingredients, stirring until sugar dissolves. Cool completely (about 45 minutes); stir in ice. (Mixture should be cold before adding to chicken.)
3. Cut chicken breasts in half crosswise. Place tea mixture and all chicken pieces in a large zip-top plastic freezer bag; seal. Place bag in a shallow baking dish, and chill 24 hours.
4. Remove chicken from marinade, discarding marinade. Drain chicken well.
5. Whisk together flour and next 4 ingredients in a medium bowl. Spoon 1 cup flour mixture into a brown paper bag or large zip-top plastic freezer bag. Place one piece of chicken in bag; seal and shake to coat. Remove chicken, and transfer to a wire rack. Repeat procedure with remaining chicken, adding more flour mixture to bag as needed. Let chicken stand 30 minutes to form a crust.
6. Pour oil to depth of 1 1/2 inches into a cast-iron Dutch oven; heat over medium heat to 325°. Fry chicken, in batches, 15 to 22 minutes or until browned and done, turning occasionally. Drain on a wire rack over paper towels.
Note: If using a 12-inch-wide (2 1/4-inch-deep) cast-iron skillet, pour oil to depth of 1 inch.