McDonald's replaced its original barbecue-focused menu with its streamlined hamburger system in 1948.
Richard and Maurice McDonald had operated a drive-in restaurant since 1940, serving a broad menu that included barbecue foods. After closing for several months, they reopened in 1948 with a much smaller selection centered on hamburgers, cheeseburgers, fries, milkshakes, and drinks.
This change was a branding milestone because it made the restaurant easier to recognize and reproduce. Customers received the same small group of inexpensive items quickly, while the kitchen was organized around assembly-line preparation.
The date is sometimes confused with 1955, when Ray Kroc founded the corporation that became McDonald's Corporation and opened his first McDonald's franchise in Des Plaines, Illinois. The simplified menu and service concept came from the McDonald brothers' 1948 redesign, years before Kroc's corporate expansion.