Sources for authentic recipes

Authentic is a very slippery question. Recipes change over time, and even the most down-home recipes are prepared differently from village to village and even house to house. As far as I know, cilantro and lime are very typical ingredients in guacamole - they are certainly included in both the Diana Kennedy and Rick Bayless standard versions, and those authors are known for their meticulous research in Mexico.

Authentic is a myth and a moving target. Bless your food with delicious instead.

Cooking is using what's around and tastes good. All cuisines evolve.

If you want to approximate traditional dishes, consult a nutritional anthropology text or a culinary historian (they exist, really). More practically, ask a Mexican. (Or a Swede. Or a Brit... Per the cuisine). Preferably one who lived there. Better one who cooked there. Ideally one whose grandma cooked there.

Also, a "customary" recipe sounds like one you'd find in a tourist-shop that sells regional cookbooks. They might not be up to the standards of modern regional cuisines, but the whole "modern" part probably means it's not "authentic" anyway.

I don't think you'll find a single source that provides authentic recipes for a wide variety of different ethnic foods. I think you'll need to find a good source for each type of food, unfortunately. The only book I have that I'd consider authentic is The Breath of a Wok, which covers a wide range of Chinese food. Maybe each ethnicity could use a question for "What's an authentic and comprehensive book for [type of food]?"

I use a line of cookbooks available in the US called Best Recipe which tends to be very good. They have an International Version which goes through many different types of food. It's a great book, but it's not particularly authentic. So if you're looking for breadth and good recipes, it's a good one. But I'm not sure it would suffice to cook for a native nor meet the standard set forth in the question.

A good place to start is to research what ingredients are seasonally and regionally available at the same time/place as the main ingredient(s), what flavor profiles are common to the overall zeitgeist of the regions cuisine, and finally consider the cost of various ingredients and how that compares to the perceived socio-economic class traditionally ate the dish.

Since your example is guacamole, can I very highly recommend (ta-da) Authentic Mexican, by Rick Bayless? This cookbook has quite a bit of background on all the dishes, their history, how they are traditionally prepared and eaten in Mexico, and how the (presumably American) non-Mexican cook can prepare them in non-Mexican kitchens. Though not Mexican himself, Rick Bayless is widely considered to be one the world's foremost experts in Mexican cuisine, and one can comfortably rely on his pronouncements of what is and is not authentic. (His recipe for basic guacamole includes both lime and cilantro.)

Drawing on this example, if interested in authenticity in foreign cuisines and you can't go to the country in question to experience the food in person and see how people there actually eat, the key is to find a book like Authentic Mexican—one that comes from someone with deep experience in the cuisine that has substantial amount of prose (not just recipes) describing how dishes are prepared and enjoyed in the country. If you read the book and learn how a cuisine arises from the native (and introduced) crops that thrive there, and how economics and other historical conditions have affected the culture that produced the cuisine, you can come to a deeper understanding of the cuisine and know why a particular dish is authentic or not. Alternatively, you could watch episodes of a cooking program hosted by an expert in a cuisine (like Julia Child for French cuisine or Rick Bayless for Mexican) and you'll learn from their asides and commentary what makes different dishes authentic. I'm a big fan of Rick Bayless's show Mexico One Plate at a Time because in each episode he goes to Mexico and shows how a particular dish or ingredient is prepared and enjoyed in Mexico, then he goes back to Chicago and shows you how to prepare some version of it in his home kitchen.

But generally speaking, in my opinion, what contributes most to authenticity is not necessarily the choice of ingredients, but more the manner of preparation and the milieu of service—your guacamole might be just like one made in Mexico City or Guadalajara, but if you're eating it by dipping fried corn tortilla chips into it, that's not really authentic at all. In Mexico, traditionally, guacamole would be eaten rolled into a corn tortilla or dolloped onto some other dish, like a taco. Chips-and-dip are more of an American tradition, not a Mexican one.

I think there's a few aspects here --

• "authentic" as in, they really cook this dish in that region.
• "traditional" as in, they've cooked this dish in that region for quite some time.

Of course, traditions develop over time, and cooking techniques and ingredient availablity changes over time, so a "traditional" dish might only be a century or two old.

If you're concerned about recent corruptions due to more recent changes in globalization (eg, overnight shipping of produce, external influences), I'd go with old cookbooks. Of course, I also volunteer at a library managing the sale of donated books, so I have an easy and cheap source (just got 3 more yesterday). But check at yard/garage sales, car boot sales, flea markets, estate sales, library book sales, used book stores, etc.

For US regional cooking, I like church and community cookbooks; for foreign cooking, I think I have the majority of the Time Life "Foods of the World" series that was published in the late 1960s.

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And if you want to get really picky about "authenticity", you also have to consider that many of the great recipes in a region came from peasant dishes. Is it being authentic to the dish to get ingredients flown in from the other side of the world to make it, or would it be better to find a reasonbly priced fresh local alternative?