Authentic Chinese Food in Brooklyn?
Start with Grand Sichuan House in Bay Ridge (read the posting history first to narrow down the great dishes) and take it from there.
Dim Sum @ Pacificana (Sunset Park) - try their fish balls.
813 55th St, Brooklyn, NY 11220
Grand Sichuan House
8701 5th Ave, Brooklyn, NY 11209
All up and down 8th Ave in Sunset Park, as the previous post mentioned. I'm not sure how to judge a Chinese restaurant's Chinese-ness exactly, but the two times I've been to Lucky Eight , about 80% of the patrons were Chinese, the waiter was struggling to communicate with us, and the menu had more than one amusing mistranslation. The food was dang tasty too.
5204 8th Ave, Brooklyn, NY 11220
8th Avenue between about 45th and 62nd Streets has a bunch of them. The menus are filled with numerous choices of rather odd sounding to me things to eat like reptiles and unusual animals, and many choices of various organs that I had wouldn't have imagined anybody ate until I saw it there. The menus are in Chinese but most have English translations. Some may not be translated, and you may have difficulty finding anybody that works there that speaks English.
I've eaten in a couple of them when I felt adventurous. In each instance, I was the only round-eye in the place. Not only the dishes, but the flavors and aromas are completely different than the typical "Americanized" Chinese take out joints. In every instance, I found them awful. Not because the food was bad, but rather because I didn't like the flavors at all. I trust that ought to be authentic enough for you.