Tuesday, February 13 is Fat Tuesday, the day before the start of the Lenten season. It is the last day of indulgence for Catholics in preparation for the sacrifice of certain luxuries.

As with many European traditions in America, over time the pastry known as paczki has become increasingly important in our culture. That is especially true in the Midwest, where Polish immigrants settled and brought with them the paczki tradition.

For many Midwestern bakeries, Fat Tuesday (or Paczki Day) is one of the biggest days of the year. They prepare for the rush of customers who will grab these special treats during the final hours before Ash Wednesday.

One of the oldest bakeries in the Midwest is European Bakery in Jackson, Michigan. It has been around since 1913, opened by a Polish immigrant looking to bring delicious paczkis to America. Jim McCann carries on his grandfather’s paczki tradition 105 years later. Beginning on Monday, February 12, the team at European Bakery started the process of making 900 dozen paczkis for Tuesday. Over half of those 900 dozen were pre-ordered, with the rest of the 10,000+ paczkis to be picked up in-store.

For Bridgeport Bakery in Chicago, a rush of Chicagoans was expected for the big day. The bakery will sell nearly 33,000 paczkis before Ash Wednesday, a total owner Ron Pavelka never would’ve predicted when he first opened the store 44 years ago.

“When we first started out, it was a couple cans full, and we were happy to sell those. Now, it’s probably the biggest holiday we have,” Pavelka tells CBS Chicago. “Basically, we cannot make enough. We will sell out today.”

For Bridgeport Bakery, European Bakery, and many other bakeries specializing in this Polish pastry, they will more than double or triple their usual staff in preparation. This will barely be enough to make the necessary paczkis that will be in demand on Fat Tuesday, a fantastic celebration for both bakeries and their customers alike.