Paczki come in several jelly-filled varieties, though the traditional flavour is prune. (CBC/Susan Aitken)

In Windsor, Ont., it's the day your taste buds crave, and your arteries dread — Fat Tuesday — better known in the border city as Paczki Day.

And it's a growing tradition, with tens of thousands of the 500-calorie treats being sold for Mardi Gras.

The paczki, pronounced poonsh-key, is for many, Polish pastry perfected.

Depending on the recipe, paczki can have up to 500 calories and 25 grams of fat. (CBC/Susan Aitken)

It's a round, jelly-filled dough ball tossed in icing sugar traditionally eaten on Shrove Tuesday to mark the end of celebrations before the Christian period of Lent begins on Ash Wednesday.

Packzi purists order the prune-filled variety, but the pastries also come in raspberry, lemon, strawberry, prune, blueberry, apple, custard and occasionally chocolate.

Depending on the recipe, one paczki packs 25 grams of fat.

Polish immigrants brought the paczki

The paczki phenomenon came to Windsor from the city of Hamtramck, Mich., just across the Detroit River.

'People don't care about the calories.'—Ali Bazzi, Sunrise Bakery

A rush of Polish immigrants arrived there in the early 20th century seeking work at the Dodge Brothers automobile factory.

By 1970, the area was 90 per cent Polish, and the popularity of the paczki had grown beyond the borders of Hamtramck.

"Every year is more paczki. This year we're making the record," said Ali Bazzi, from Sunrise Bakery.

"It's a once a year thing," said Bazzi. "People don't care about the calories."

Bazzi, who is Lebanese, has been making paczki for 15 years. He said making paczki isn't about being Polish, it's about good business sense.

His bakery had orders for 42,000 paczki on Tuesday, 17,000 of which were purchased by the Caesars Windsor casino.

$10 a dozen

The going rate for a dozen paczki is $10 or $1 a piece. Even Canadian bakery giant Tim Hortons is getting in the game, selling paczki for 95 cents each, or $7.50 a dozen.

Sunrise Bakery expected to produce 42,000 paczki for Fat Tuesday 2010. (CBC/Tom Taylor)

Paczki production was in full swing at Blak's Bakery all day Monday and overnight into Tuesday.

For 92 years, Blak's has used a family recipe, and everyone in the clan is expected to pitch in and help on Paczki Day. Twenty-six of them expected to box 24,000 paczki this year.

Most paczki are pre-ordered, and by 10:30 a.m. Tuesday, Blak's was sold out.

The next Shrove Tuesday, or Paczki Day, falls on March 8, 2011.