Shrimp toast, the classic dim sum order of white bread smeared with shrimp paste and then deep-fried, has gone big-time. I've tasted upscale takes at Clark's Oyster Bar in Austin and Xiao Bao Biscuit in Charleston, SC. Trendy Hakkasan in New York stuffs it with foie gras and charges $22. My current fave? The sandwich version at Son of a Gun in Los Angeles. Imagine fried shrimp crossed with a croque-monsieur and you get the idea.