[4][5] Lassen placed his own blend of ground steak trimmings between two slices of toast and sent the gentleman on his way, so the story goes, with America's alleged first hamburger being served.

[13] Louis' Lunch makes their hamburger sandwiches from ground steak made from a blend of five cuts of beef.

The hamburgers are prepared with cheese spread, tomato or onion,[4] then served on two square pieces of toasted white bread.

[16][17][18] The stoves[19] use hinged steel wire gridirons[20] to hold the hamburgers in place while they cook simultaneously on both sides.

[26] Many others claim to be the creator of the hamburger, including Charlie Nagreen,[27] brothers Frank and Charles Menches, Oscar Weber Bilby, and Fletcher Davis.

[30] However, it gained national recognition at the 1904 St. Louis World's Fair when the New-York Tribune namelessly attributed the hamburger as "the innovation of a food vendor on the pike.

"[29] In 2000, the Library of Congress recognized Louis' Lunch as the creator of the hamburger after being backed by United States Representative Rosa L.

[34] Detractors of the Louis' Lunch claim include Josh Ozersky, a food editor for New York magazine.

[10] Ozersky's book also notes earlier claimants and recognizes Walter Anderson for creating the modern hamburger.

[37] Renny Loisel, public relations director of the Greater New Haven Convention and Visitors Bureau, submitted an affidavit and letter from the New Haven Preservation Trust and noted that the Library of Congress recognizes Louis' Lunch for creating the first hamburger, but the evidence was denied.

According to an internet poll, Louis' Lunch placed third and Loisel noted that despite the evidence it was more about theatrics than truth.

Another issue is that the spread of the burger happened largely at the World's Fair, from tiny vendors that came and went in an instant.

"[11] Critics of the restaurant hinge on its dislike of condiments, particularly ketchup; customers who ask for it are ejected from the premises.

Tom Gilbert wrote, "Louis’ Lunch is a very friendly place as long as you get with the program, which always has been about serving quality beef and making sure that nothing ruins or upstages it.