March 14, the day when mathematics and baked goods collide, is known as Pi Day. And, in our food-obsessed world, Pie Day.

Pie, we know. For those who skipped geometry class, pi is the ratio of a circle’s circumference to its diameter, a constant number that works out — when it’s rounded to two decimal places — to 3.14.

March 14th — 3/14 — get it?

“It used to be that the only people who knew about Pi Day were the nerd guys, you know?” said Dave Hulett of Dave the Pie Guy in south Minneapolis. “But it’s gone mainstream, and now everyone wants pie on Pi Day.”

When Hulett invokes “everyone,” he’s not exaggerating. Well, not much.

“Thanksgiving, Christmas and Father’s Day have traditionally been the top three pie sales days each year,” he said. “But I think Pi Day is going to beat Father’s Day. Last year, it was neck and neck. There’s even a chance that it could beat Christmas.”

Let that be a warning to those seeking out a slice of banana cream or lemon meringue on this day of days: Plan ahead, and go early.

“Every year, I think that I’ve got enough,” said Hulett. “And every year, it’s never enough.”

Birchwood Cafe

Owner Tracy Singleton recalls that Key lime pie has been a menu staple for forever. “Since we opened, I think, so that’s almost 24 years,” she said. Citrus is kind of an oddity for a kitchen that focuses on local, seasonal ingredients. “As far as I know, we haven’t been able to grow Key limes here in Minnesota,” she said with a laugh. “But it’s always Key lime pie season. And the whipped cream, that’s local.” And delicious, as is the pie, and it should be, what with two dozen years of pie-making practice. There’s a strawberry version, too (“the berries are local, from our freezer stash from last summer, and the eggs and flour are local, too,” said Singleton), and the restaurant’s team of bakers are also turning out coconut cream, apple and German chocolate cream pies. Slices $6 to $7.

3311 E. 25th St., Mpls., 612-722-4474, birchwoodcafe.com

Breaking Bread Cafe

“Baking is patience,” said Audley Rolle, who has been turning out lovingly rendered baked goods at the cafe for the past two years. “It’s just working with good ingredients and then giving them time.” That’s certainly the philosophy behind his superb sweet-potato pie, which starts by rubbing the starchy roots with olive oil and roasting them, “until they’re perfect,” he said. Once out of the oven, they’re the backbone of a creamy, not-too-sweet treat, one of many reasons (waffles, smoked brisket and biscuits with turkey gravy are a few others) to make a habit of this casual neighborhood destination. Slice $3.95, whole pie (48 hours’ notice preferred) $20.

1210 W. Broadway, Mpls., 612-529-9346, breakingbreadfoods.com

Dave the Pie Guy

Of the dozen or so treats that fill the counter at this cozy south Minneapolis shop and cafe, one pie stands out above all others: streusel apple. Owner Dave Hulett incorporates four different apples, and relies upon the fruit’s inherent sweetness — unlocked through a two-hour baking process — rather than heaps of sugar. “There’s a half-cup of sugar in this entire pie,” he said. “I let the apples do all the work. The longer you bake them, the sweeter they get.” The secret ingredient behind his flaky pie crust? Feta cheese. For his popular version of French silk (“I can’t keep it on the shelf; it fights for first place with apple,” he said), Hulett relies upon a premium chocolate bar and works toasted pecans into the crust. Other standards include banana cream and Key lime, and he also offers mince meat (raisins, dates and cherries, marinated in brandy) on a year-round rotation. Most slices $4.95, most whole pies $25.95 and $32.95.

3544 Grand Av. S., Mpls., 612-871-9544, davethepieguy.com

The 50’s Grill

It’s not just burgers and malts that keep the kitchen busy at this family-friendly Brooklyn Center landmark. The counter at the front door is stocked with a huge variety of baked-on-the-premises pies. So many classics are present and accounted for, ranging from a lattice-top beauty filled with tart cherries to a spiky-topped lemon meringue. Blueberry-peach, pecan, raspberry, fresh apple, coconut cream, you name it, it’s probably here, or at least it’s in the kitchen’s repertoire. Buy them by the slice ($4.95), but the real deal is the whole-pie price; at $12.95 (plus $1 pie tin deposit), they’re one of the Twin Cities’ better bargains. There’s a savory side, too: single-serving (the portions are generous) heat-and-eat chicken and beef potpies, at $6.45 a pop.

5524 Brooklyn Blvd., Brooklyn Center, 763-560-4947, 50sgrill.com

Hi-Lo Diner

A slice of pie is a natural at this meticulously restored 1957 diner, and for Pi Day, baker Rosa Yapangui — with help from executive chef Mitch Robbie and sous chef Miriam Alvarez — will be featuring four playful options: black-bottom banana cream (chocolate ganache topped with bananas sliced into vanilla custard), passion fruit (cream cheese layered with a passion fruit custard and cardamom-scented whipped cream), Hand in the Jar (Oreo crust with chocolate and peanut butter lusciousness) and ginger-pecan. Slices $5 (go a la mode for an additional $1.50), but on Pi Day, prices on all slices are cut by $1.

4020 E. Lake St., Mpls., 612-353-6568, hi-lo-diner.com

Honey and Rye Bakehouse

Those who haven’t indulged in baker/owner Anne Andrus’ signature pie haven’t been living life to the fullest. It’s a play on the eternal flavors of the Almond Joy candy bar, and the marriage of chocolate and coconut have never been more appealing, especially since it starts with a flaky, beyond-tender, all-butter crust. Other classics — Key lime, apple and banana cream — are part of the mix, too, and they’re first-rate. Slices $4, whole pies $28. For home bakers in search of a tutorial from a professional, Andrus is offering Pie Dough 101 on April 2, part of her ongoing classes series. Cost is $75, reservations at honey-and-rye.com/classes.

4501 Excelsior Blvd., St. Louis Park, 612-844-2555, honey-and-rye.com

Pie & Mighty

Owners Rachel Swan and Karen Mattison specialize in pies, selling them at pop-up events, and naturally they are diving headlong into Pi Day, taking their pop-up piefest to St. Paul’s Brake Bread. Doors open at 8 a.m. for slices of their dreamy cherry, banana cream and maple-pecan pies, made with their proprietary butter-lard crust. Be sure to sign up for the Pie Loop (at pieandmightymsp.com), a spam-free e-mail list that makes it easy to order pies on the 364 days of the year that aren’t Pi Day. Slices $5.

Brake Bread, 1174 W. 7th St., St. Paul, 651-300-9136

Salty Tart

Chef/owner Michelle Gayer is celebrating the occasion with hand pies. “I want you to be able to take them and go, you know what I mean?” she said. “They’re easier to eat in your car. I feel like a slice of pie is a commitment. You need a plate, and a fork; it’s a whole other layer of packaging.” Expect to encounter a sweet and a savory option, both using butter-laden crust (“I’d love to get into lard, someday, I’m not going to lie,” Gayer said with a laugh. “But we’re all about butter”). The former is a housemade orange marmalade-cream cheese with rosemary, the latter is a combination of potato, bacon, Asiago cheese and onions cooked in Rubbish Red Ale from LynLake Brewery. The brewery is also supplying its Sideburns stout for a caramel that Gayer layers into a chocolate pie that serves two. “Or, depending on who you are, one,” she said with a laugh. Find all three at both Salty Tart locations, starting at 7 a.m., and starting at 5 p.m. at the brewery. Hand pies $4, chocolate pie $7.

Salty Tart, 2940 Harriet Av. S. and 289 E. 5th St., St. Paul, saltytart.com. LynLake Brewery, 2934 Lyndale Av. S., Mpls., 612-224-9682, lynlakebrewery.com

Turtle Bread Co.

The go-to source for well-made pies, year-round. The assortment changes with the calendar, but right now the bakery cases are filled with a half-dozen beauties that include crumble-top cranberry-pear, Key lime, pecan, apple, pumpkin and chocolate cream. The flaky, buttery-infused crusts are tops in their class, and because the whole pies are obviously fashioned by hand (we’ll have to wait for summer for the great-looking lattice-top versions, which are rhubarb-, berry- and peach-filled works of art) and served in sturdy pie tins (which require a $3 deposit), they look as if you’ve baked them yourself, a dividend for those who don’t have time to bake but want to sneak one over on their pie-loving friends and family. Slices $4.99, whole pies $26.99.

4762 Chicago Av. S., Mpls., 612-823-7333; 3421 W. 44th St., Mpls., 612-924-6013; and 4205 E. 34th St., Mpls., 612-545-5757, turtlebread.com

Bakers Square

On March 14 (and Pi Day Eve, March 13), the chain that places pie in the spotlight is offering a deal: Those buying whole pies can take $2 off the purchase price.

Nine Twin Cities locations, bakerssquare.com

Looking to make your own pie? Try this Strawberry-Banana Cream Pie recipe. Feeling really ambitious? Here are some tips on making your own crust.