TWENTY-FIVE years out of restaurant school, I should know how to cut up a mango. But it wasn't until I was noodling around online recently that I finally learned why I make a mess of every one. In a video on iFoods.tv, an Irish chef in a T-shirt used a small knife to slice off each end of a mango so that it would stand upright, then pared away the skin in downward strokes before carving the flesh off in chunks down to the seed. In a little more than two minutes he had a bowlful of perfectly diced sweet fruit.

If that sounds confusing, it was as clear as HDTV on my computer screen. The videos proliferating like morels on countless websites are the ultimate do-it-yourself cooking lessons. The quality can be stunning, the information easy to grasp, the entertainment value priceless. Watch filmmaker Robert Rodriguez make tortillas from scratch on YouTube and you may never buy the supermarket kind again.

While the Food Network is struggling to find its way, and "Top Chef" is focusing on stunts over substance, the Internet might finally be the medium aspiring Gordon Ramsays have been waiting for. The best of these online cooking lessons provide diversion and depth -- watch cooks attempt stock in a slow cooker at Crash Test Kitchen or be transported to a chapati-baking Indian grandmother's side at Manjula’s Kitchen or get your bechamel-as-pizza-sauce education with a healthy dose of snark at Food Wishes Video Recipes. Not that there's anything wrong with the straightforward approach: Epicurious runs a have-it-your-way mini cooking school with short videos on techniques as basic as lighting a grill or as lifesaving as how to patch pie dough.

Learning to cook from television was never practical even with a set in the kitchen; it's impossible to follow along without the ingredients prepped. DVDs aren't the answer either, but they at least offer the possibility of pausing the action. You still need to get the discs in and out of the player without getting flour and butter all over them. Computers in the kitchen aren't outlandish; at least one new refrigerator comes with Internet access built in.

Some websites charge for programming, but incessant trawling has convinced me that some of the best things online are free. If not every cooking "teacher" with a video is as skilled with a camera as with a knife, the ambition and/or knowledge often admirably compensate. Many of the videos at Tasty Food, for instance, are by experts in one dish, whether an esoteric Italian cake (ciambellone) or tuna meatballs.

The most useful food vlogs (video blogs) tend to be quirkier, and they are in the minority. The preponderance seem to follow the tired television script: "Hi, I'm so-and-so and I'm going to show you such-and-such." A great cooking segment jumps right in and starts slicing and dicing.

How-to videos are a booming business online, but finding great ones on food isn't as easy as typing in "cooking lesson" on YouTube. That turns up a handful of nondescript choices, or maybe spoofs such as a geek frying eggs on his computer. Many of the how-to conglomerate sites now being hailed as the maps to the online wilderness are exercises in frustration too; I've given up on hard-to-navigateSquidoo and eHow.

The food world online is so scattered, you can turn up a parody of Christopher Walken cooking and an actual video of him cooking (a chicken on a vertical roaster with pears alongside). It's hard to say which is weirder, and both rate four stars on YouTube. At the other extreme, you can learn how Ferran Adrià of El Bulli in Spain makes apple "caviar" with his bag of molecular tricks at StarChefs.

Vlog variety

AMONG THE many worthwhile detours, Crash Test Kitchen is a vlog produced by a couple of amateurs with more energy than expertise, but they do experiment -- with sometimes happy results (that stock made in a slow cooker). The very clean, very spare site is just a very British man and woman who have healthy curiosity paired with personality; their cooking skews toward treacle pudding and porridge in the slow cooker, but they will try anything.

Rouxbe bills itself as "a professional cooking school in the comfort of your own home," for $99 a year or $199 for lifetime membership. The site, run by the Northwest Culinary Academy of Vancouver, in Canada, is gorgeous, but I can only guess at how well it delivers its professional-level curriculum, because I was unable to register for a free trial. The sample videos are beautifully produced, though; you can watch a quick recipe summary or the entire step-by-step process of making Thai green curry paste or potato gnocchi or salade Lyonnaise (with frisée, bacon and poached egg).

Rouxbe also boasts that it is ad-free, no small consideration these days -- I'm amazed at how many sites that I have prowled are overrun with "lose belly fat fast" ads and worse. Cook’s Illustrated also carries no advertising on its site, but it charges for access beyond a handful of free videos. The freebies up now are models of terseness and clarity: how to make perfect pasta clocks in at about a minute, how to make a fluffy yellow cake only slightly longer.

Cookshow lets anyone in the world create a video and upload it to the site, with wildly varying results from the 1,180 contributors. The recipes in French are worth sitting through to bone up on a second language; the bonus is that you learn how to make an apple tart with chestnut crème rather than something like chicken and asparagus casserole courtesy of an American "instructor." The print recipes can be translated into English so that you can actually make them.

Similarly, iFoods.tv -- home of the mango epiphany -- is both a vlog and a community of cooks, with professionals and amateurs giving lessons. All are in English, often the king's.

Foodtube is a grab bag of recipe demos that unfortunately is difficult navigate; however, it has potential for anyone with patience who is curious about anything ethnic, such as Caribbean conch fritters, or bizarre, such as bulls' testicles and rattlesnake (not together).

New York restaurateur Zarela Martinez recently added videos to Cooking With Zarela, demonstrating Mexican techniques and ingredients: how to remove thorns from nopales, make tamales, render lard. Martinez's are very short, unlike Rodriguez's "10-minute cooking school," extras from his DVDs posted on YouTube in which he demonstrates "Sin City breakfast tacos" and puerco pibil (from "Once Upon a Time in Mexico"). Both leave you with an indelible understanding of how the recipes work.

No passport required

THE possibilities for exploring far-flung cuisines, though, may be the most promising part of cooking lessons online. You can see almost anything transformed from ingredients to dinner: fresh ravioli in Tuscany at Tasty Food, a tomato turned into a rose at Meilleur du Chef, fried mussels on the street in Thailand at Enjoy Thai Food. The best of these are produced in the countries where the foods originate, with no adjustments for inaccessible ingredients or forbidding concepts. In an oddly high-tech way, it's like having Mom pass down recipes the old way: by showing, not writing.

But my biggest enlightenment since the mango has come from the young American in Paris working in a three-star restaurant who vlogs at Ms. Glaze. Her engaging classes demystify many of the basics of French cuisine, and one in particular gave me my nerve back. I have not braved puff pastry since restaurant school, but she makes feuilletage look as easy as toast. She could get me to consider shucking oysters next.

food@latimes.com