Orange-flavored Chicken

Why I Love This Recipe
This is a fairly involved recipe. Not difficult, per se, but time consuming. It does, however, make extremely good orange chicken. Best made for company.
If you have a deep-fryer, it's going to make your life easier. Remember not to crowd the pan when you fry - just a few pieces of chicken at a time. Any more and the temperature of the oil will drop too much, and your chicken will be greasy and soggy. I know a lot of people don't cook with distilled vinegar but it adds brightness and acidity without imparting any off flavors. This recipe came from - where else - Cook's Illustrated.
Ingredients You'll Need
MARINADE & SAUCE
1 1/2 lbs boneless, skinless chicken thighs, trimmed and cut into 1 1/2" pieces
3/4 cup low-sodium chicken broth
3/4 cup juice, 1 1/2 tsp grated zest and 8 strips orange peel from 2 oranges
6 tbsp distilled white vinegar
1/4 cup soy sauce
1/2 cup packed dark brown sugar
3 medium garlic cloves, pressed or minced
1 1" piece fresh ginger, grated
1/4 tsp cayenne pepper
1 tbsp plus 2 tsp cornstarch
2 tbsp cold water
8 small whole dried red chilis (optional)
COATING AND FRYING MEDIUM
3 large egg whites
1 cup cornstarch
1/4 tsp cayenne
1/2 tsp baking soda
3 cups peanut or vegetable oil
Directions
FOR THE MARINADE AND SAUCE: Place chicken pieces in a 1-gallon zipper-lock bag; set aside. Combine chicken broth, orange juice, grated zest, vinegar, soy sauce, sugar, garlic, ginger and cayenne in large saucepan (with at least 3-quart capacity); whisk until sugar is fully dissolved. Measure out 3/4 cup mixture and pour into bag with chicken; press out as much air as possible and seal bag, making sure that all pieces are coated with marinade. Refrigerate 30 to 60 minutes, but no longer.
Bring remaining mixture in saucepan to boil over high heat. In small bowl, stir together cornstarch and cold water; whisk cornstarch mixture into sauce. Simmer sauce, stirring occasionally, until thick and translucent, about 1 minute. Off heat, stir in chilis and orange peel; set sauce aside.
FOR THE COATING: Place egg whites in pie plate; using fork, beat until frothy. In second pie plate, whisk cornstarch, cayenne and baking soda until combined. Drain chicken in colander; thoroughly pat chicken dry with paper towels. Place half of chicken pieces in egg whites and turn to coat; transfer pieces to cornstarch mixture and coat thoroughly. Place dredged chicken pieces on wire rack set over baking sheet; repeat with remaining chicken.
TO FRY THE CHICKEN: Heat oil in 11" or 12" Dutch oven or straight-sided saute pan with at least 3-quart capacity over high heat until oil registers 350 degrees on an instant-read or deep-fry thermometer. Carefully place half of chicken in oil one piece at a time; fry until golden brown, about five minutes, turning each piece with tongs halfway through cooking. Transfer chicken to large plate lined with paper towels. Return oil to 350 degrees and repeat with remaining chicken.
TO SERVE: Reheat sauce over medium heat until simmering, about 2 minutes. Add chicken and gently toss until evenly coated and heated through.