When I was in college, the Chinese delivery guy knew the code to my dorm. I lived on Chinese delivery for my first three years of college, until a sorority sister found a caterpillar in her lo mein and that was it for me until there was another place to order from, because yuck.
I order Chinese occasionally and lemon chicken is one of my favorites. This recipe from Ken Hom is much better than delivery unless you're in the mood for some battered and fried chicken. This chicken isn't crunchy because there's no batter. The sauce is much more citrus-y than some delivery places that make a cloying, overly sweet lemon sauce. I doubled the sauce so that it would flavor my rice. However, the recipe below is a single batch of the sauce. The recipe is relatively simple but it does require a bit of physical work because you have to drain your wok and wipe it down. So if you have a wok with short handles, oven mitts are a good thing to have around.
From Ken Hom's Complete Chinese Cookbook
2 boneless, skinless chicken breasts (preferably medium or small, if your chicken looks like it lived on anabolic steroids, one large breast would probably do)
1 egg white
2 tsp corn starch
1 1/3 cups peanut or vegetable oil
5 Tbsp chicken stock
3 Tbsp fresh lemon juice
1 Tbsp sugar
1 Tbsp light soy sauce
1 1/2 Tbsp Shaoxing rice wine or dry sherry
1 Tbsp finely chopped garlic
1 tsp dried red chili flakes
1 tsp corn starch mixed with 1 tsp water
2 tsp sesame oil
Sliced green onions
1) Cut the chicken into 2 inch strips and mix them in a bowl with the egg white and corn starch. Leave in the fridge for 20 mins while you do the other prep work.
2) Heat a wok (or large frying pan) until it's very hot and then add the oil. When the oil is very hot, remove the wok from the heat and add the chicken pieces. Cook for 2 minutes, stirring vigorously to make sure the chicken doesn't stick together. After the chicken has turned white, quickly drain it in a stainless steel colander set over a bowl (or in your sink - it's less messy).
3) Wipe out the wok and reheat it. Add all the sauce ingredients except the cornstarch mixture and the sesame oil. Bring it to a boil over high heat and then stir in the corn starch mixture. Simmer for 1 minute.
4) Put the chicken back in the wok and toss to make sure it's coated by the sauce. Then add in the sesame oil and mix well. Serve over rice and garnish with green onions.