Trim ends off green onions and cut light green and white part into 1" sections.
Mix all other sauce ingredients in 2-quart saucepan. Reserve.
Pull skin off breasts, then pull chicken meat from bones. Slice meat into 1" strips, then crosswise to make 1" chunks.
In bowl large enough to hold chicken, add egg white to water chestnut
flour. Beat mixture with a single chopstick (not an egg beater or whisk).
Stir chicken pieces into egg mixture to coat thoroughly. Marinate 5 minutes.
Deep-frying
Heat cooking oil in wok or deep-fryer to medium heat (you'll need more oil for deep-fryer).
Fry peanuts until they are a light tan color; if a test peanut browns quickly, turn down heat.
Remove peanuts with strainer or slotted spoon; drain on paper towel or paper bag. Reserve.
Turn up heat slightly for chicken. Test a chunk first: chicken should raise to surface immediately & brown in about 2 minutes.
Deep-fry coated chicken chunks until golden brown (no more than 8 chunks at a time. Use long chopsticks or spatula to keep pieces separate while they are frying. Remove with long chopsticks or slotted spoon. Reserve.
Sauce
While deep-frying chicken, heat sauce to simmer.
Add green onions & peanuts about a minute before serving.
At the last minute, add chicken pieces to sauce, mix quickly & serve.
TIPS:
Water chestnut flour gives a lighter crust than cornstarch, though the latter may be substituted.
