Almost all Chinese restaurants in the USA have this dish, but have you ever wondered: who was General Tso? What has he got to do with chicken? This website will explain:
If you read the biography below (written by a military historian who believes in very, very long sentences), you'll notice that while Tso was a successful 19th C. Chinese general, chicken is not mentioned even once. It's pretty clear that General Tso didn't have the time to invent or even taste the dish named after him. So where did it come from?
My theory: It was invented in the mid-1970's, in NYC, by one Chef Peng. Chinese food in New York was different in the early '70s; while there were a quite a few Chinese restaurants around, they were all Cantonese. Bland food, served in a decor straight out of the 1950's (think: Too much RED).
Around 1974, Hunan and Szechuan food were introduced to the city, and General Tso's Chicken was an exemplar of the new style. Peng's, on East 44th Street, was the first restaurant in NYC to serve it, and since the dish (and cuisine) were new, Chef Peng was able to make it a House Specialty, in spite of its commonplace ingredients.