Heat up a pan over medium high heat. combine all the ingredients under marinade and soak the diced chicken in it for about 15 minutes.
Cook the chicken until it's white, drain and put aside.
Wipe the pan clean (this is to make sure nothing gets burned when you heat up the pan again) and heat up to medium high.
Combine sauce ingredients in a small bowl and set it aside.
Drizzle oil on the pan again, saute onions, celery and green onions for about 1 minute. you want to keep the vegetables crunchy.
Add the already cooked chicken and the sauce mixture into the pan and cook until the sauce thickens.
Serve over steamed or fried rice.
I thought this was good but not as good as Panda Express black pepper chicken. I doubled the sauce and thought it was very good except, if I do cook this again, I will use a little less black pepper.