As previously mentioned, Chengdu has a "Little Tibet". Since Tibet is generally quite poor, a lot of Tibetans come down into Sichuan to live and work, and since Chengdu is the nearest big city, there's a good-sized Tibetan community there living in a neighbourhood that's not unlike a Chinatown in the West.
I found a Tibetan restaurant, and sat down to a lunch of yak stew and butter tea (po cha). While a really heavy meal for the dead of summer, I couldn't pass up the opportunity. I've had yak before and liked it, and the only Himalayan restaurants I can find in Canada are Nepalese, not Tibetan.
The stew had thick flat starchy noodles and pieces of potatoes, as well as a few pieces of yak. Yak is not unlike beef and very much like bison, though a bit fattier. It was a hearty and filling soup, and definitely something I'd try again.
I've met several people who hated po cha - I think they might have just been expecting it to be sweet instead of salty. (Big difference between milk tea and butter tea!) The po cha came in a metal teapot with a small cup, and you could certainly taste the three ingredients - black tea, yak butter, and salt. Traditionally po cha is churned, but it is now more often made in a blender for convenience. It's really more like a soup in its own right, and quite tasty too!