Baker Jessica Cook didn’t realize how seriously some of her customers are about pi until she got phone calls a year ago.

It is her third Pi Day since opening J&G Pastries just off the historic Woodstock Square in late 2023, Cook said, but the first time she’s baking pies to recognize the date. In her first years, she didn’t know much about the holiday celebrating the mathematical constant of pi – about 3.14 or π, the ratio of a circle’s circumference to its diameter – or that March 14 also has become a day to eat pie in its honor.

“I felt like it just seems so obvious” that bakers would embrace the day to make pies – and for customers to order them, Cook said.

“Last year, I had a ton of calls from people looking for something” on the day, she said.

She’s joining bakers from around McHenry County in making sure customers looking to celebrate the circle that is pie – and pi – can get their share.

Pies are what Crystal Lake’s Pots and Pies Bakery does, owner Auriane Ugalde said, adding that they’ve celebrated the day for three years now.

“We started promoting it on social media last week,” Ugalde said. Some customers will order ahead for one of the 10 sweet pies she and her bakers are baking that day, on top of the six or seven in their regular rotation.

“We also get a good deal of foot traffic on the day of,” she said.

Ugalde tries to match her pies to the season and the holiday. Because St. Patrick’s Day is next week, she also has savory pies – corned beef and cabbage and shepherd’s pie – on the menu.

This year is the first Pi Day for Black Market Bakery in Crystal Lake, which opened in June.

“One of the front-of-house people suggested we do apple pie for Pi Day,” said Angelica Cress, one of the bakers there. They’re making 6-inch, homemade, butter crust apple crumble pies and plan to offer a limited number of them Friday and Saturday on a first-come, first-served basis.

Many of the bakeries contacted said they were making smaller pies for customers looking to celebrate but who may not want a full 9- or 10-inch pie.

Rosie’s Gluten Free Sweets, also in Crystal Lake, is making 5-inch rounds in apple, cherry and peach, ensuring those who can’t have wheat gluten can enjoy some pie.

Huntley’s Village Inn Family Restaurants will sell their pie slices for $3.14 on Saturday, too.

It isn’t just the pastry makers who get into Pi Day.

Banushi’s, a new Italian and pizza restaurant in Algonquin, also is planning its take on Pi Day, according to manager Albert Banushi. On Saturday and Sunday, the eatery will offer a medium cheese pizza for $3.14 with the purchase of a large regular pizza. Additional toppings for the cheese pizza are an additional charge.

He’d heard friends talk about Pi Day in the past, he said, adding, “I thought it was about pie” and not the mathematical pi.

They decided to offer a special for the day when the Algonquin Area Chamber of Commerce asked if anyone was doing something to celebrate, Banushi said.

“People who know, know” about the day and its intent, he said; by celebrating it “you grab a subset of customers with a different interest.”

If you go, restaurants and bakery’s with Pi Day promotions:

• Banushi’s pizza and pasta, 2749 W. Algonquin Road, Algonquin, 224-333-0129, banushispizza.com.
• Black Market Bakery, 86 N. Williams St., Crystal Lake, 815-526-3000, Instagram.com.
• J&G Pastries, 203 Main St., Woodstock, 815-403-1553, Facebook.com.
• Pots and Pies Bakery, 67 E. Woodstock St., Crystal Lake, 815-354-9934, potsandpiesbakery.com.
• Rosie’s Gluten Free Sweets, 5150 Northwest Hwy., Crystal Lake, 815-880-5100, rosiesgfsweets.com.
• Village Inn Family Restaurant, 11713 Main St., Huntley, 847-669-5858, villageinnhuntley.com.