It's not real Chinese food. It's the kind that comes out of a jar. My Chinese boss says there is basically one distributor for a particular type of "Chinese" restaurant, and they sell vats of sweet-n-sour sauce and frozen pre-breaded meat/shrimp to various restaurants--the restaurant owners just hire line cooks, and the quality of the food varies according to the skill of the line cook, who might dress the food up with fresh veggies or chopped herbs. PF Chang's is in this vein, only instead of the frozen pre-breaded stuff they actually use fresh meats and bread them in house. But it's the same sauce-from-a-can base with spice-from-a-jar and veggies added, so it's better than the line cooks who do only the frozen pre-breaded stuff with plain canned sauce.
Seriously, if you want to make it at home, the secret is getting the right canned sauce from the Asian market. Most Thai restaurants, even the spendy ones, use sauce from a can.
Out this way, if you want real Chinese food, you go to Boston's financial district and be prepared to pay good money. But the dumplings and dan dan noodles, they are as good as any you'd find in Chengdu.