It’s the right time of year for baking whoopie.

If I have made you blush, rest assured what follows is a strictly G-rated affair.

Whoopie pies are an all-American baked good that looks like a puffed-up sandwich cookie but tastes more like a cupcake. Think cake with frosting that doesn’t get all over everything.

Just exactly where the titillating name came from is unclear, but anyone who grew up in the Northeast knows whoopie pies have long been lunchbox, bake sale and convenience store staples.

Whoopie pies trace their origins from both Pennsylvania, where they are sometimes called “gobs,” and Maine, where thousands attend an annual whoopie pie festival. Last year, Maine’s Legislature and the Pennsylvania Dutch Convention & Visitors Bureau got in a lover’s spat over paternity of the treat. Eventually the Maine Legislature settled for naming the whoopie pie the official state treat.

Amy Treadwell grew up in Massachusetts. When she moved to San Francisco, few souls in the food-forward city knew what a whoopie pie was, let alone a gob. But since she wrote “Whoopie Pies: Dozens of Mix ‘Em, Match ‘Em, Eat ‘Em Up Recipes” (Chronicle) in 2010, the sweet has caught on across the country. In fact, this year’s sales of the cookbook topped sales from the year it was released.

“Any mom-and-pop store had home-baked whoopie pies near the cash register, but now you’re seeing them at wedding dessert tables and parties,” says Treadwell, co-author of the cookbook with Sarah Billingsley. “I even saw four of them in a clear plastic clamshell at Trader Joe’s.”

While researching their book, the authors (also conveniently editors at Chronicle Books) discovered whoopie pies have other colorful monikers, such as scooter pies, chocolate drops, round dogs, cream cakes, moon pies and black moons. Whatever you call them, they have become an easy vehicle for delivering a variety of interesting flavor combinations.

The traditional whoopie pie is chocolate cake with a marshmallow filling. But thumb through “Gobba Gobba Hey” (Bloomsbury) by Steven Gdula, a transplanted western Pennsylvania native who sells his wares from a food cart in San Francisco, and you’ll find gourmet variations ranging from Strawberry Gobs With Strawberry Balsamic Filling to Persimmon and Mascarpone Gobs.

The most unusual flavor Treadwell has encountered?

Horchata, a drink popular in Spain and Mexico made by steeping nuts, grains and chufa, a tuberous root from Africa with a nutty flavor. But Treadwell and Billingsley came up with some mighty interesting fillings of their own, including root beer, maple-bacon and bacon-chive goat cheese.

“There are as many flavors of whoopie as would be any kind of cake or cupcake,” Treadwell says.

Whoopie pies are easy to make and require very little in the way of equipment. A stand mixer is extremely helpful, although you can also use a hand-held mixer or a spoon. The shape of the cookies varies depending on the recipe and whether you choose to use a pastry bag, scoop or a specialty whoopie pie pan.

“I’m a lazy baker,” Treadwell says. “I always spoon because I can’t be bothered to load up a pastry bag.”

Billingsley, however, prefers the pastry bag for perfectly round, equal size cakes. Piped frosting also gives a pretty, frilly edge.

“I haven’t tried the pan,” Treadwell says. “I think it gives a weird edge that looks strange to me, but I can’t argue with the convenience.”

In 2010, Wilton, the cake pan and decorating supply company, teamed up with Sur La Table to offer a whoopie pie pan with traditional round indentions. The beauty of the nonstick pan is that it knocks the fussy pastry bag out of the equation.

Nancy Siler, vice president of consumer affairs for Wilton, says the pan has been “wildly popular.” So popular that the company has developed a seasonal line of whoopie pie pans, including hearts, bunnies, pumpkins, stockings, Christmas trees and gingerbread boys.

“Whoopie pies are quirky, and the great thing is you can make a batch and have gift-ables for a number of people instead of a whole cake for one,” Siler says.

Wilton conducted a Facebook survey of 775 customers last February and found 77.2 percent planned to make Valentine’s treats for friends, co-workers, children and relatives, in addition to sweethearts. And, of course, Wilton encourages its customers to decorate to the hilt, which can be more difficult when the icing is inside.

“Obviously we decorate on top, but the perimeter of a whoopie pie also is a good place to decorate,” Siler says.

Which begs the question, if you put frosting on top of a whoopie pie, doesn’t it become a cupcake?

Decorating on top of whoopie pies is more common in the United Kingdom, where whoopie pies are making a splash. “It’s a big trend, and they’re selling really well in bakeries, but they embellish them a lot by putting more glazes on top of the whoopie pies and adding fruit to the fillings,” Treadwell says.

Siler suggests “zipping up” whoopie pies for Valentine’s Day with “red” themes, including red velvet and raspberry pies, or decorating the frosting perimeter with crushed peppermint, nonpareils and colored sugars. 

By Jill Wendholt Silva

(McClatchy Newspapers)

(Distributed by MCT Information Services)

Tips

Equipment:

You will need a mixer (preferably a standing one), baking sheets, a 2-tablespoon scoop for 4-inch whoopies or a melon baller for 2-inch whoopies, parchment or waxed paper and an optional pastry bag.

Size doesn’t matter:

A classic whoopie pie measures about 4 inches in diameter, but many bakeries are creating a bite-size treat. There are really no rules, says Amy Treadwell, co-author of “Whoopie Pies” (Chronicle Books).

Google “whoopie pies” and you might notice that some have domed tops while others are more flat. The consistency of the batter tends to determine the cosmetics, although whoopie pie pans do produce cakes with a more pronounced lip.

There are no rules on how much filling is stuck between the cakes. Spread it with a knife or use a fancy pastry bag.

Why shortening?

Resist the temptation to substitute butter in recipes that call for vegetable shortening. Crisco is a necessary ingredient for “lift, lightness and that classic rounded whoopie shape,” Treadwell says.

A sticky situation:

Throughout the Northeast, whoopie pies are most often sold in individual cellophane packages, which can cause a “skin” to form on the plastic. “The outside layer of the cake often sticks to the plastic, but that’s part of the charm,” the authors write.

I made the mistake of stacking the cakes on top of one another after they had cooled, slightly marring the perfect tops. If you must stack your cakes, be sure to place parchment or waxed paper between the layers.

Make ahead:

Assembled pies can be kept in an airtight container for up to 3 days.

The cakes can be frozen for up to a month, and most fillings hold up well under refrigeration for up to a week. Filled whoopie pies also may be frozen for an hour on a baking sheet, then individually wrapped and stored. They also will keep for up to a month.

(Recipes from “Whoopie Pies” (Chronicle Books) by Sarah Billingsley and Amy Treadwell)