The Shamrock Shake is a seasonal green mint flavored milkshake dessert sold at some McDonald's restaurants during March to celebrate St. Patrick's Day in the US, Canada, Ireland, Australia, New Zealand and the UK.
Origin
Hal Rosen, a McDonald's owner and operator from Connecticut, created the first Shamrock Shake in 1967.[1][2] Three years later, in 1970, the Shamrock Shake debuted in select locations in the United States.[3] Rogers Merchandising in Chicago created the shake. Initially, the shake was lemon/lime flavored with vanilla ice cream, lemon/lime sherbet, and vanilla syrup. By 1973, the shake was merely a green colored vanilla shake, eliminating the lemon/lime sherbet. It is now mint flavored.[4]
Shamrock Shakes are sold at select U.S.