According the HoustonPress the frozen margarita was invented by Mariano Martinez of Mariano's Mexican Cuisine, in where else? The "Big D".
The Frozen Margarita debuted at Mariano's Mexican Cuisine in Dallas.
Mariano got the recipe from his Dad who used to mix up virgin versions for customers who then would add their own Tequila to get around Dallas' dry liquor laws. When the laws changed in the early 70's Mariano adapted it to make it "production ready." Key to his success was modifying a slushy machine. Even back then technology was king. The drink was enjoyed by everyone from Trini Lopez to Lee Trevino but it was Southern Methodist co-eds, who were looking for a frothy sweet drink to "function" with, that popularized it. Chi-Chi's, Chili's, Azteca's and Applebee's all thank you.
