What is Tex-Mex cuisine?
Food historians tell us TexMex cuisine originated hundreds of years ago when Spanish/Mexican recipes combined with Anglo fare. TexMex, as we Americans know it today, is a twentieth century phenomenon. 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. TexMex restaurants first surfaced ouside the southwest region in cities with large Mexican populations. The gourmet Tex Mex "fad" began in the 1970s. Diana Kennedy, noted Mexican culinary expert, is credited for elevating this common food to trendy fare. These foods appealed to the younger generation.
What is Tex-Mex?
"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. But it is foreign in that its inspiration came from an alien cuisine; that it has never merged into the mainstream of American cooking and remains alive almost solely in the region where it originated. "
---Eating in America. Waverly Root & Richard de Rochemont [William Morrow:New York] 1976 (p. 281)
[1940s] "Tex-Mex. A combination of the words "Texan" and "Mexican," first printed in 1945, that refers to an adaptation of Mexican dishes by Texas cooks. It is difficult to be precise as to what distinguishes Tex-Mex from true Mexican food, except to say that the variety of the latter is wider and more regional, whereas throughout the state and, now, throughout the entire United States."
[1950s] "Mexican restaurants, whos popularity coincided with the arrival of large numbers of Mexican immigrants after 1950, have for the most part followed the from and style of what is called "Tex-Mex" food, and amalgam of Northern Mexican peasant food with Texas farm and cowboy fare. Chili, which some condsider Texas's state dish, was unknown in Mexico and derived from the ample use of beef in Texan cooking. "Refried beans" are a mistranslation of the Mexican dish frijoles refritos, which actually means well-fried beans. The combination platter of enchiladas, tacos, and tortillas became the unvarying standards of the Tex-Mex menu, while new dishes like chimichangas (supposedly invented in the the 1950s at El Charro restaurant in Tucson, Arizona) and nachos (supposedly first served at a consession at Dallas's State Fair of Texas in 1964. ) were concocted to please the American palate. One Tex-Mex item that may someday rival the pizza as an extraordinarily successful ethnic dish is the fajita. introduced at Ninfa's in Houston on July 13, 1973, as tacos al carbon. 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. 80-1)
"In the good old days, Texans went to "Mexican restaurants" and ate "Mexican food." Then in 1972, The Cuisines of Mexico, an influential cookbook by food authority Diana Kennedy, drew the line between authentic interior Mexican food and the "mixed plates" we ate at "so-called Mexican restaurants" in the United States. Kennedy and her friends in the food community began referring to Americanized Mexican food as "Tex-Mex," a term previously used to describe anything that was half-Texan and half-Mexican. Texas-Mexican restaurant owners considered it an insult. By a strange twist of fate, the insult launched a success. For the rest of the world, "Tex-Mex" had an exciting ring. It evoked images of cantinas, cowboys and the Wild West. 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 
America's First Cuisines. Sophie D. Coe
American Food: The Gastronomic Story. Evan Jones [chapter III "Padres and Conquistadores"]
Cuisines of Mexico. Diana Kennedy
Encyclopedia of American Food and Drink. John F. Mariani [separate entries for specific foods--fajita, tamale, chalupa. ]
Food Culture in Mexico. Long-Solis& Vargas
The History of Food. Maguelonne Toussaint-Samat, "The History of Cereals, Maize in the West" (pages 164-176)
New Mexico Cooking: Southwestern Flavors of the Past and Present. Clyde Casey
Oxford Companion to Food. Alan Davidson [Mexico]
Oxford Encyclopedia of Food and Drink in America. Andrew J. Smith [Mexican American Food]
Pre-Hispanic Cooking. Ana M. Benitez
Que Vivan Los Tamales! Food and the Making of Mexican Identity /Jeffrey M. Pilcher
The Story of Corn. Betty Fussell
You Eat What You Are. Thelma-Barer-Stein ("Mexico")
Bunuelos & churros
The history of bunuelos and churros can be traced to ancient peoples. fritters were known to many cultures and cuisines; each evolving according to local tastes and customs. These foods were introduced to Mexico by Spanish settlers. There are several foods closely related to bunuelos and churros: sopaipillas & fry bread. In other countries, simliar recipes evolved as doughnuts, funnel cake, and waffles.
"Most countries have their version of bunuelos, or fritters, either sweet or savory, and they are certainly great favorites throughout Spain and Latin America. In many parts of Mexico bunuelos are made of a stiffer dough, which is rolled out thin anywhere up to 12 inches in diameter and then fried crisp and staked up ready for use. In Uruapan. they are broken into small pieces and heated\ quickly in a thick syrup of piloncillo, the raw sugar of Mexico. These of Veracruz are very much like the churros of Spain, but flavored with aniseeds, and served with a syrup."
"At every Spanish festival or carnival, one is sure to find a huge cauldron of bubbling oil where Churros are quickly fried, shaped into loops, and threaded into reeds that are then knotted for easy carrying. They are meant to be purchased immediately after frying, usually by the dozens, and are munched on by visitors as they wander about taking tin the sights. Churros are nothing more than fried batter of flour and water, but they are essential to a Spanish breakfast, dipped either in sugar or in a cup of coffee or thick hot chocolate. If one is out on an all-night binge--a juerga, as it is called--it is the custom to end the evening by eating Churros and hot chocolate at the churreria, or churro store, which opens by dawn."
---The Foods and Wines of Spain. Penelope Casas [New York:Knopf] 1982 (p. 342)
[NOTE: this book has a recipe for churros, we can send you a copy if you like]
The Foods and Wines of Spain /Penelope Casas
---recipes for several different kinds of bunuelos; pages introducing desserts (p. 340-1) sum up the ingredients used and holiday connections.
Burritos, as we Americans know them today, pair ancient culinary traditions with contemporary expectations. What makes burritos different from most other Mexican-American foods is the metamorhpasis of this dish. We tracked down the earliest print references for "burritos" cited by food history in American/English reference books. They are nothing like the burritos we are served today. "What" modern burritos are is easily defined. "When" & "where" did the change happen? Early 1960s, Southern California. "Who" & "why" remain a mystery. Our survey of historic newspapers suggest food trucks played a roll. Burritos are efficient, economical, easy & delicious.
"Burrito. A tortilla rolled and cooked on a griddle, then filled with a variety of condiments. Burritos are a Mexican-American staple. The word, from Spanish for "little donkey," first saw print in America in 1934. If fried, the burrito becomes a chimichanga."
---Encyclopedia of American Food and Drink. John F. Mariani [Lebhar-Friedman:New York] 1999 (p. 48)
"Burrito. A Mexican dish consisting of a maize-flour tortilla rolled round a savoury filling (of beef, chicken, refried beans, etc.) 1934: E. Ferguson. Mexican Cookbook. 33. Burritos (Little Burros). Mix tortillas. but mold them thicker than usual. Make a depression in the middle of each and fill with chichiarrones. 1962 Mulvey & Alvares Good Food from Mexico (rev. ed.) iii.81 Burritos in the northern part of Mexico and in the southwestern part of the United States are quite different. 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."
". in the Sonora and southeastern Arizona, some people make tortillas out of wheat, as well as, corn. Not just tortillas, but huge regional tortillas, often well over twenty inches in diameter. Wrapped around some sort of filling, they are called burros or burritos, depending upon the size. Burros can be filled with anything. If you deep-fry a burro it becomes a chimichanga--a truly local dish from Another Arizona or northern Sonora."
---Tucson's Mexican Restaurants. Suzanne Myal [Fiesta Publishing:Tucson AZ] 1997 (p. 14) 
"Burritos (Little Burros)
Mix tortillas according to recipe on page 85, but mold them thicker than usual. Make a depression in the middle of each and fill with chicharrones, made according to recipe on page 30, and chopped. Bake in a moderate oven." (p. 33)