Blue Moon ice cream knows how to distinguish itself in a freezer case: with a color resembling pureed Smurf.

"The moment customers come in, especially children, it's the first thing that catches their eye," said Brian White Jr., owner of 2 Scoops in St. Paul, one of the few places in Minnesota that serve the unusual treat.

Like its namesake celestial event, Blue Moon sightings can be rare once you get beyond its home turf of Michigan and Wisconsin. Here in Minnesota, a handful of ice cream shops and a devoted fan base have helped Blue Moon expand its Midwestern reach — with a cult status enhanced by its mysterious origins and enigmatic flavor.

Katie Romanski, owner of Minnesota Nice Cream in Minneapolis and Stillwater, is one of the flavor's most vocal local evangelists.

"I'm here to bring Blue Moon across the border and teach people what it's about and how delicious it is," she said. "It takes a little bit of convincing, but when people try it, then they're like, 'When is Blue Moon coming back?' "

Her affinity for the flavor dates back to her childhood in Wisconsin Rapids. "Every time we went to get a scoop of ice cream, I always had Blue Moon and I never knew what it was," she said.

When Romanski offers Blue Moon in her soft-serve rotation, reactions are split between instant recognition and total befuddlement. "The Wisconsin people will be like, 'Blue Moon, I love it!' Other people are like, 'Does that taste like beer?' We do a lot of explaining."

Kyle Farizel, owner of Cold Front in St. Paul, forgoes words in favor of having curious customers rely on their taste buds: "Our best description is just to let people try it," he said.

"I've I heard everything under the sun really," said Darrell Hauge, owner of Flamingos Ice Cream & Treats in Fridley, describing his customers' response to his shop's top-selling version of Blue Moon. "Just last week somebody said they thought it was like amaretto."

The internet has oh-so-many theories about what Blue Moon tastes like, including coconut, pistachio, nutmeg, marshmallow, cotton candy, cantaloupe, bubble gum and blue curacao.

The best description of Blue Moon may be that it "tastes like summer." But the most common one is what White tells his customers: "Have you ever had Froot Loops cereal? The way the leftover milk tastes is exactly the way Blue Moon tastes."

What, exactly, does "froot" milk taste like?

Kellogg's reportedly creates the cereal's flavor (all six loop colors taste the same) from an orange-lemon-cherry-raspberry-apple-blueberry-lime blend. The remaining milk mostly tastes sweet, with vague hints of tartness of nuttiness ... with a bit of imagination, it is a bit like Blue Moon ice cream.

Mysterious origins

Only an artisan ice cream maker would soak Froot Loops in milk to infuse its flavor. Everyone else relies on commercial flavorings.

The official formula for Blue Moon originated with a decades-old Milwaukee flavor company eventually purchased by Chicago-based Weber Flavors, which now holds the trademark. Some credit a Milwaukee chemist named Bill Sidon with having developed the flavor in the 1950s, but patent filings and newspaper clippings suggest it may have been decades earlier. (Adding to the confusion, other parts of the world have similarly bright-blue, hard-to-place flavors known as Smurf or Crema del Cielo, aka Sky Cream.)

Flavor companies are tight-lipped about the nature of their formulas, which has only increased speculation. Plenty of home chefs have attempted to reverse-engineer Blue Moon ice cream, with the most-cited recipe on the internet calling for vanilla pudding, raspberries and lemon extract.

Weber Flavors uses the descriptors: "citrus, spice, fruity cereal, sweet & sour, citrus honey, and citrus vanilla." After the company's owner once told a reporter their Blue Moon flavor was made with an ingredient typically used to hide bitter flavors, one online sleuth theorized it was the food additive castoreum — a natural secretion that beavers use to mark their territory.

Recipe revealed

We may be overthinking Blue Moon's mysteries, says Romanski, who is among those who believe Blue Moon tastes like almond, which is also the description used by Cedar Crest, a Wisconsin-based ice cream maker that supplies several local shops. (Chocolate Shoppe Ice Cream Company, which produces Blue Moon for its own parlors in Madison, Wis., and several in the Twin Cities, is in the Froot Loops camp.)

Romanski is among the rare ice cream shop owners who concoct their own flavors and she happily shared her recipe for Blue Moon: a three-to-one ratio of imitation almond extract and lemon. "And don't forget the blue food coloring," she quipped.

"When you mix those together, something magical happens," Romanski said. "It's such a mysterious flavor, but it's so simple."

Metro ice cream shops serving Blue Moon

Call ahead for availability.

2 Scoops Ice Cream Eatery: 921 Selby Av., St. Paul; 651-645-0227; 2scoopseatery.com

Cold Front: 490 S. Hamline Av., St. Paul; 651-508-1469; coldfrontmsp.com

Flamingos Ice Cream & Treats: 1258 E. Moore Lake Drive, Fridley; 763-572-2078; flamingosicecream.com

Licks Unlimited: 31 Water St., Excelsior; 952-474-4791; licksunlimitedmn.com cq

Nelson's Ice Cream: 920 Olive St. W., Stillwater; 651-430-1103; 454 S. Snelling Av., St. Paul; 651-313-7268; nelsonsicecream.biz

Nita Mae's Scoop: 101 Judd St., Marine on St. Croix; 651-433-0137; nitamaes.com

Minnesota Nice Cream: 807 NE. Broadway, Mpls., 612-259-7053; 308 Chestnut St. E., Stillwater; 651-571-3199; mnnicecream.com

For online ordering, Chocolate Shoppe Ice Cream sells its Blue Moon pints and 3-gallon tubs through icecreamsource.com