Dictionaries and food history sources confirm the first print evidence of the term "Tex Mex" occured in the 1940s.
Linguists remind us words are often used for several years before they appear in print. "Tex-Mex food might be described as native foreign food, contradictory through that term may seem, It is native, for it does not exist elsewhere; it was born on this soil.
By a strange twist of fate, the insult launched a success.No one knows when or where it acquired the name fajita, which means girdle' or'strip' in Spanish and refers to the skirt steak originally used in the preparation...Only in the last decade has refined, regional Mexican food taken a foot-hold in American cities, reflecting not only the tenets of Tex-Mex cookery by the cuisines of Mexico City, the Yucatan, and other regions with long-standing culinary traditions." ---America Eats Out, John Mariani [William Morrow: New York] 1991 (p.Dozens of Tex-Mex restaurants sprang up in Paris, and the trend spread across Europe and on to Bangkok, Buenos Aires and Abu Dhabi.
Tortilla chips, margaritas and chili con carne are now well-known around the world." --- Houston Post, 6 part series, all online: Los Angeles Times Cookbook: Old Time California, Mexican and Spanish Recipes  History & evolution: Recommended books: America's First Cuisines, Sophie D.342) [NOTE: this book has a recipe for churros, we can send you a copy if you like] RECOMMENDED READING: The Foods and Wines of Spain/Penelope Casas ---recipes for several different kinds of bunuelos; pages introducing desserts (p. Now a popular dish in many restaurants and taco stands in California and Texas are northern burritos, which are made by folding a flour tortilla around a mound of re-fried beans, seasoned to taste with chili." ---Oxford English Dictionary, 22nd edition Burros?