Centerpiece : Doughnuts are selling like hot cakes these days, and their purveyors are working their buns off to satisfy the demand.

At 1 o’clock every morning, Mary Canale is midway through her labor: mixing, kneading, pulling, shaping, cutting and frying dough. She will press on until 5 a.m., when the tired but hungry will start surging in and, through half-open eyes, order from rote memory: glazed, old fashioned, chocolate, buttermilk, frosted, twisted, cinnamon. They will do this in increasing states of consciousness until about 10 a.m., when finally the crowd will slacken. By then a good dent will have been made in the 400 or so doughnuts Mary made in the night.

Still, there will be just enough doughnuts remaining to carry Mary’s late-coming customers till 4 p.m., when Mary or her husband, John, will start baking all over again, making the round-the-clock doughnut tally exceed 600. “You never know who will show up, or when,” she says. “I take pride in my bake, and also that you can still have a choice whenever you come in.”

Mary slips home to catch some sleep as early as 6 a.m. or as late as 10 a.m., only to return most days at 4 p.m., go home again at 8, and then return again at 11 p.m. to continue the “bake,” as she calls it. She works as few as 15 hours and as many as 20 a day.

This is her life at Donut Cafe on 1st Street. Doughnuts have been Mary’s life for 22 years.

But never before has she been so busy. Never has she sold so many doughnuts. Never, she will tell you, has she found herself at the center of such a burgeoning business.

Her sales are up $6,000 monthly over two years ago. Mary’s not sure why except to say, “I work real hard.” But she has more competition than ever before, a fact that only amplifies her success.

Five years ago, there were five doughnut shops in this town. Now there are 12 (one, it seems, either within or proximate to each of Simi’s major strip malls) and many are turning a brisk business.

Besides the Canales’ Donut Cafe are Donut Citi, Donut Delight, Donut Depot, Best Donuts, Donuts Plus, Donut Queen, Dundee Donuts, East Side Donuts, Ernie’s Royal Donuts, Simi Donuts and Donut Inn. This is to say nothing of the profusion of doughnuts available at Simi’s supermarket bakeries and the major-brand boxed doughnuts alongside them.

Simi Valley, however, is not some strange anomalous field of doughnut wars. Doughnuts are enjoying ubiquity throughout Ventura County, now jammed with 73 doughnut shops--making a starchy per capita presence of one shop for every 9,200 residents. Saticoy, a tiny 1,200-person hamlet, has two shops, making it possible for anyone there to walk to the store for fresh fried dough. Oxnard, the county’s largest city, has 18.

Why is this so?

Why, in the wake of a health-crazed ‘80s and in the sobering grip of a prudent low-fat ‘90s, are brown globes of fat-saturated dough multiplying like space mutants?

“Couldn’t tell you,” says Mary Canale. “People do get in the habit, though.”

This may understate things, actually.

The Canales’ shop, for example, enjoys orders from local businesses. The continental breakfast at nearby Travelodge is custom-baked by Canale. Thrifty Car Rental orders six dozen a day. And one day a month, Countrywide Mortgage calls in for a whopping 90 to 100 dozen doughnuts.

Countrywide, it turns out, orders the doughnuts as part of a “goodwill day” toward employees, says Laura Lippman, a company spokeswoman based in Pasadena. Countrywide’s Simi offices house nearly 1,200 people, and each person is invited to take one doughnut. At Countrywide’s Pasadena and Plano, Tex., offices, “goodwill day” includes bagels and muffins--but in Simi it is straight doughnuts, and apparently not by accident.

“It’s a way of saying thanks on payday,” says Lippman, adding, “the doughnuts are there to boost morale.” But high morale and goodwill went out the window the day Countrywide forgot to call Canale for doughnuts. “People were in shock,” says a laughing Lippman. “They were on the phone all morning saying: ‘Hey, where’s my doughnut?’ ”

From Bible to Bakery: Doughnuts, or some doughy antecedent form of them, have a long history of stirring passions.

Take the Bible. Appropriate forms of sacrifice are discussed in Leviticus 7:12, which says that “cakes mingled with oil . . . of fine flour, fried,” might be used as offerings to God. While it is doubtful that divine volition drove cultures to mix flour with water, egg, yeast and drop the goo balls into boiling oil, something deeply rooted had to shepherd the incipient, morphing doughnut through countless cultures. The Italians had the zeppola for centuries. Ditto the beignet for the French. The Germans did everything imaginable to pure dough, including frying all manner of shapes of it in straight lard.

The Dutch actually made doughnuts as we recognize them today, according to food historian and writer John Mariani, and the Pilgrims, he reminds us, spent 1607 through 1620 in Holland, where they learned how to make doughnuts. Indeed, there is some culinary argument to be made that when you first think of Plymouth Rock, it should not conjure Harvest, Turkey but instead Plain, Old-Fashioned. The pilgrims did many things, but lasting among them was the introduction of doughnuts to New England kitchens.

The doughnut never knew from calorie or fat counts. Diedrich Knickerbocker’s History of New York, published in 1809 and cited in Mariani’s Dictionary of American Food & Drink, contains the lethal passage: The table “was always sure to boast an enormous dish of balls of sweetened dough, fried in hog’s fat, and called doughnuts or olykoeks (oil cakes) . . . a delicious kind of cake, at present scarce known in the city excepting in genuine Dutch families.”

Well. The Pennsylvania Dutch made up for that. They were able to carry on the grand tradition with fat-fried doughnuts called fastnachts on Shrove Tuesday as the last sweet before Lent. Then they poked a hole in the thing and started dunking it in coffee.

As doughnuts spread through American culture, they got dressed up: in sugar, chocolate and vanilla icing, cinnamon. They’d take a poke in the side, too, but just enough to get filled with jellies and creams. There were, it seemed by the turn of the century, no apparent limits for flavoring or shaping them. (Note: Only a decade ago the largest doughnut, a single 74-pound Old Fashioned, was boiled in Richardson, Tex., but this may have more to do with Texans than with culinary destiny.)

The doughnut became synonymous in this country with Comfort, Home, Mother. The Salvation Army’s idea of bringing relief to U.S. troops in World War I was to send to France young women who boiled oil in garbage pails, plopped in the dough balls, otherwise known as doughboys, and handed out doughnuts.

Returning soldiers, according to doughnut historian Sally Levitt Steinberg, inspired her grandfather to break the single remaining barrier to the doughnut’s omnipresence in America. Adolph Levitt, a Russian immigrant who failed at dry goods in Milwaukee, sensed the wartime popularity of doughnuts and field-tested a boiler in the window of a Harlem, N.Y., bakery. He found, inexplicably, that people would gather in great number on the sidewalk to simply watch doughnuts fry. If he could somehow mechanize the cooking of doughnuts, he might be onto something big.

By 1920 Levitt had it figured out. His patented doughnut machine (a conveyor flipped the doughnuts mid-boil) made doughnuts quickly (960 an hour) and Levitt a wealthy man. The bakers and carnivals and purveyors who bought the machines filled America with doughnuts.

By the time America got into World War II, Levitt was ready for not only the Salvation Army but also the Red Cross: He rented out, at discount, his doughnut machines for use in specially rigged doughnut trucks. If the technologies of war had advanced, so, too, had our capacity to fry enough dough fast enough to ensure continuous doughnut supply--from the trenches to the mess hall.

Doughnuts would, in time, completely penetrate American culture. Johnny Carson would discuss with guests such as Red Skelton their membership in the American Dunking Assn.

Doughnut franchises sprouted up, outlets lining highways. Dunkin Donuts would become the largest by far and, at its “university” in Massachusetts, would not only teach franchisees how to operate a shop but would also encourage innovation of the sort that has resulted in the doughnut with a dunking “handle,” or protruding nub.

Independents would sprout up between the chains, which phenomenon has also been the clear trend in Ventura County.

Through all this explosion of doughnut commerce, however, little attention was paid to the frying medium--that is, the hog’s fat of a Dutchman’s 18th-Century table in New York City.

Yet it’s the frying medium--not the doughnut’s otherwise decadent jellies and creams and sugars--that sends people to the treadmill, packs on the pounds and jams the arteries with fat deposits.

Nutrition Nightmare: Today’s frying fat is commonly referred to as oil, but almost universally it is shortening. The difference is critical. Shortening contains not only more saturated--or artery-clogging--fat, but also large quantities of a little-known and to-date unlabeled danger called trans fat.

Trans fat occurs when plain liquid vegetable oil undergoes hydrogenation, or solidification, into shortening. It raises cholesterol and, by mechanisms not entirely understood, behaves at least as badly upon the blood as does saturated fat. “It is the worst of the fats,” says Alberto Ascherio, a researcher in metabolic chemistry at Harvard University.

Last year the Center for Science in the Public Interest in Washington took a plain cake doughnut from Dunkin Donuts to a laboratory for measurement of trans fat as well as other fats. The result was startling: While the doughnut was advertised as having four grams of total fat, it also carried five grams of trans fat. This made the humble brown, unsugared, uncoated cake doughnut match a McDonald’s Big Mac in containing nine grams of cholesterol-raising fat.

The comparisons continue to startle. The No. 1 choice at Mary Canale’s shop, as it is everywhere in America, is the yeast-risen glazed doughnut. While it appears to the eye as only slightly more odious than a plain cake doughnut, figures on file with the USDA show that it contains twice the amount of fat as an eclair with custard filling and chocolate icing.

Calorically, the picture is as bad. The simple glazed doughnut has nearly twice the calories of a Mallomar chocolate cookie and more than twice the calories of a Hostess Cherry Pie. (As food deceptions go, perhaps most striking of all is that the Dunkin Donuts oat bran muffin has 60% more calories and 20% more fat than the glazed doughnut--but muffins are another category of sin altogether.)

Doughnuts have not come too far from the hog fat days, once trans fat is figured in. But this fact, owing perhaps to the doughnut’s pacifying and sinful-pleasure-giving capacities, hasn’t damaged sales.

As Dale Ogar, editor of the Berkeley Wellness Letter, puts it: “Oh, God. What’s the point? Doughnuts are those things you eat when you must. They’re so obviously lethal, you eat them knowing that.”

Immigrants’ Choice: In Ventura County, the impulse seems to strike more than just once in a while. The score so far, in number of doughnut emporiums: Oxnard, 18; Simi Valley, 12; Ventura, 10; Camarillo, eight; Newbury Park and Thousand Oaks, five each; Moorpark, four; Fillmore, Santa Paula, Ojai and Saticoy, two each; Meiners Oaks, Oak View and Agoura Hills, one each.

John Park runs Donut Citi in Simi Valley. Park, trained as a chemical engineer, left his native Korea in 1977 after starting a shirt-exporting business. In Los Angeles, he found it difficult to run the same business from the other end, as an importer. He became an aerospace machinist in Gardena instead.

When his industry declined, he heard from a pastor friend at a Riverside church that doughnuts were a booming business.

“White man’s food, the doughnut,” is how Parks puts it. “Simi’s a good place to sell doughnuts.”

He, like Canale, keeps a ridiculous schedule because “it is so hard, so many hours to make it work.” But he, too, is selling doughnuts, making it work. And so, too, are the others, all from the same premixed flours available on the open market, and any number of them are Cambodian immigrants such as Simone Leng at Donut Depot.

Canale has a theory as to why so many of the newer doughnut shops are run by immigrants.

“Because Americans don’t want to do the work. It’s too hard, too long,” she says.

It’s only fitting that the protean doughnut should become the quarry of zealous immigrants--a burgeoning young class of Americans willing to do what it takes to sell, for small but steady profit, the oldest of comforts--hog fat or not.