Louis dressing is a salad dressing based on mayonnaise, to which has been added red chili sauce, minced green onions, and minced green chili peppers. It is commonly used as a dressing for salads featuring seafood, such as a Crab (Crab Louis, the King of Salads) or Shrimp Louis.
The origin of the dressing is disputed. The Olympic Club in Seattle, The Davenport Hotel in Spokane, Washington, Solari’s Restaurant, Bergez-Frank’s Old Poodle Dog Restaurant and the St. Francis Hotel in San Francisco, and the Bohemian in Portland all claim to be the home of the dressing, with the invention in either the 1900s or 1910s. In all cases, the original salad was made with Dungeness crab.