General tips
Cornstarch coating must hit completely dry chicken or the breading slides off in the fryer. Pat the cutlets bone-dry after the bath, then dredge in cornstarch with a pinch of salt and pepper. Beat one egg and dunk, then back into cornstarch. Double-coat for shatter.
Sous vide at 150°–155°F for 90 min is the ideal pre-fry doneness. The chicken comes out fully cooked and juicy, and the fryer's only job is to crisp the coating in 60–90 sec. No more guessing if the inside is done while the outside burns.
The sauce should be thick enough to coat a spoon. Soy, rice vinegar, sugar, garlic, ginger, and dried chiles, simmered until syrupy. Toss the fried chicken in the hot sauce and serve immediately - wait too long and the coating goes soft.
Use dark meat, not white. General Tso's was always a thigh-meat dish - the extra fat keeps it moist through the double-cook (sous vide + fry) and the flavor stands up to the heavy sauce. White meat washes out under the sweet-spicy glaze.
Anti-tip: don't add the chiles to the sauce - fry them in the oil first, then strain them out. That oil-infused chile flavor is the heart of the dish. Adding raw chiles to the sauce gives you heat but no depth.
Juicy tips
Use Chinese dark vinegar for authentic flavor
Dried chilies are mostly for show - remove seeds for less heat
Double-frying creates extra crispy coating