Whoopie Pies

A regional treat from the Northeast spreading throughout the rest of the country, a whoopie pie is made with two chocolate cake rounds sandwiched together with a generous helping of marshmallow creme frosting. We in Maine claim it wholeheartedly, even naming it the official state treat, but concede that Pennsylvania may have a right to claim it too.

Evocative of typical lunchbox treats, they make great homemade snacking cakes. In Maine, we don't need an occasion to eat whoopie pies; a whoopie pie creates an occasion, though they often show up at birthdays, parties, and even weddings.

Why These Whoopie Pies Are the Best

When you break it down, a whoopie pie only has two elements: the chocolate cake and the marshmallow filling. When a dessert's flavor is so simple, a recipe needs to get the details right. Here's how the details of this recipe add up to a wicked dessert.

Butter is more flavorful than oil, but oil makes moister cakes than butter. This recipe meets in the middle and uses both softened butter and vegetable oil, so you don’t have to compromise between flavor and texture. Sweetening the batter with dark brown sugar ensures a soft, moist cake and contributes a richer molasses flavor that complements the cocoa. I prefer Dutch-process cocoa powder over natural cocoa powder for this recipe. Dutch-process cocoa is darker in color and, more importantly, has a smoother, richer flavor. Using buttermilk not only adds a slightly tangy, creamy flavor, but also helps to make the cakes extra fluffy.

Marshmallow Creme Filling

Traditional whoopie pies, true to their New England roots, use a marshmallow creme filling. Marshmallow creme, invented in Somerville, Massachusetts, in the early 1900s, has the same flavor as regular marshmallows but in the form of a spreadable paste. It makes the filling for whoopie pies sweet, creamy, and slightly thicker than standard frosting. 

Creating Different Whoopie Pie Flavors

You can't go wrong with the classic pairing of chocolate and marshmallow creme , but whoopie pies naturally lend themselves to all sorts of flavor combinations. If traditional is too plain for you, or you're just looking for fun whoopie pie variations, try one of these filling flavors:

• Peanut Butter: Make the peanut butter filling by beating 1 cup softened unsalted butter, 2 cups powdered sugar, and 1/4 teaspoon kosher salt for 2 minutes. Add 2/3 cup creamy peanut butter and 1 cup marshmallow fluff and continue mixing until smooth and creamy.
• Mocha: Dissolve 1 tablespoon instant coffee in 1 tablespoon boiling water and add it to the filling along with the vanilla extract in step 9 below.
• Mint: Add 1/4 to 1/2 teaspoon mint extract to the filling in place of the vanilla extract in step 9 below.