Meet the American who made us flip for hamburgers, Louis Lassen, Danish immigrant street-wagon cook

Louis Lassen, born in Denmark, was a lunch-wagon owner in New Haven, Connecticut, when he put ground beef patties between two slices of bread. His delicious creation reshaped backyard barbecues and American culinary culture forever.

Louis Lunch is so old-school there is no history class. 

American hamburger history, at least, begins right here. The New Haven, Connecticut eatery is considered the birthplace of a national culinary treasure. 

The hamburger — specifically, the hamburger sandwich – was by many accounts first created and served by its namesake, Louis Lassen, an immigrant from Denmark. 

Lassen arrived in the United States around the age of 20 and began feeding New Haven factory workers from a food wagon in 1895. 

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He placed sizzling ground beef between two slices of bread in 1900 for a "quick and delicious" lunch, as told by local lore. 

The hamburger sandwich was born! That is, according to the most common origin story, at least.

Louis Lassen, an immigrant from Denmark, invented the all-American hamburger sandwich at Louis Lunch in New Haven, Connecticut, in 1900. The cast-iron oven to the right is still used to broil burgers at Louis Lunch in 2023.  (Louis Lunch/Lassen Family)

Others claim ownership of the first hamburger. 

But only Lassen has the stamp of approval from the Library of Congress. 

"This New Haven sandwich shop is the home of the first hamburger and first steak sandwich in U.S. history," the nation’s oldest federal institution announced in 2000. 

"Hamburgers are served only on white toast, with a choice of onion, tomato or cheese, but no condiments." 

"Hamburgers are served only on white