American food to feed to a British friend?

[kyoryu]

Barbecue. Take him to Stan's in Issaquah.

http://stansbarbq.com/

It ain't Texas or the South, but it's decent.

Also, see if he thinks lemonade is just 7-up. And if so, get him lemonade.

Delfino's in Seattle has reasonable deep dish pizza. Kylie's was better, but they closed :(