At Panda Express in El Cerrito Plaza. No kidding. I have had it several times over the past month. The first time I tried it I expected the usual fast food fare. But I was shocked to taste the best kung pao chicken I'd had in years. While the sauce wasn't true to kung pao form-it was sweet-it had an unbelievable balance between the sour and sweet flavors. The justaposition of the ginger and garlic was perfect like I had never had at even the best Chinese restaurants. Even better were the chili seeds that had been cracked open from the peppers during cooking. Unlike other restaurants where the peppers are just used as decoration, this one actually uses the peppers to flavor the dish. Make sure you have rice to absorb the spiciness!
By the way, this is the only Panda Express where I've had kung pao chicken so good. I tried it at another one in a different city and it was just ordinary. But at the location in El Cerrito Plaza you're in for a treat your taste buds won't forget!