口水雞 (kǒu shuǐ jī) is a Sichuan cold dish of poached chicken pieces in a spicy sauce. I've already covered all the characters here; 口 (kǒu) means "mouth", and I posted about it earlier this week, 水 (shuǐ) means "water", and 雞 (jī) means "chicken".
口水雞 is often "amusingly" translated as "saliva chicken" (口水 does in fact mean "saliva"), but a better translation would be "mouthwatering chicken", referring to how delicious it is. Other translations I've seen include "poached chicken with chilli sauce", "Szechuan savoury hot spicy chicken", "tender boneless corn-fed chicken in an aromatic spicy herbal sauce", and "chicken on bone with black bean in chilli oil".
As made clear by the last two of these, there doesn't seem to be any consensus on whether the chicken should be served on the bone or not. I've tried 口水雞 both ways, and haven't noticed much of a flavour difference. I think the chicken is always steamed or poached whole, before being cut up and mixed with the sauce, so it just depends on personal preference. The version pictured above, which I ate at Red & Hot restaurant in London, was served boneless.
When I made this, I used the directions for poaching a whole chicken from Maki at Just Hungry. With this method, you put the chicken in a large pot with aromatics of your choice (I used ginger and spring onion), cover with water, bring to the boil, simmer gently for 15 minutes, skimming the scum occasionally, then cover the pan, turn off the heat, and leave the chicken to cook in the residual heat of the water for 60–90 minutes.
One important thing to remember here is that there is quite a lot of water involved, and so it will take some time initially to heat up to boiling point! On my (underpowered) stove, it took nearly an hour. You'll also want to make sure to leave plenty of time for the chicken pieces to marinade in the sauce after poaching, so realistically it's probably best to start heating the water at least three or four hours before you want to serve the dish.
After poaching and cooling briefly, I removed and discarded the chicken skin (chicken skin is delicious when browned and crisp, but less delicious when poached and soggy) and used my fingers to remove the chicken from the bones in fairly large pieces. I didn't use it all in my 口水雞, but saved around two-thirds of the breast meat to use in sandwiches. I did this because (a) I was only feeding two people, and I didn't want a ridiculous quantity of leftovers, and (b) I prefer the texture and flavour of the darker meat that's found on the legs.
The sauce used in this dish really is very tasty. The first few times I tried it from restaurants, I actually wondered if there was MSG in it, but after making it myself I realised that it's simply a combination of ingredients that go very well together. I used 3 Tbsp soy sauce, 2 Tbsp Chinese black vinegar, 2 Tbsp water, 1 Tbsp sugar, 1 Tbsp minced garlic, 1/2 Tbsp minced ginger, 2 Tbsp sesame oil, 2 Tbsp home-made chilli oil, plenty of ground Sichuan pepper, and 1-2 Tbsp minced fresh coriander. All of this was mixed with the cooked chicken pieces and left to marinate in the fridge for 2 hours, except for the coriander, which I added just before serving.
Other people's recipes vary; Cooking With Mun adds rice wine to the sauce, while Kitchen Tigress includes century eggs and mung bean sheets along with the chicken. Joshiboshi uses chicken thighs instead of a whole chicken, and, like a poster on the China Travel Guide forum, fries the Sichuan pepper and some of the chill-based sauce ingredients before using. Common features include a sprinkling of sesame seeds to garnish.