Peanut butter and jelly is still one of my favorite combos, and I bake it into cakes, pies, or pastries regularly. This whoopie pie recipe is my ode to a PB & J: The bread is cake and the peanut butter is blended into a marshmallow crème. The jam hidden inside is the perfect surprise when you bite into it!
Makes 16 whoopie pies
Difficulty: Medium
Make Ahead and Storage: Whoopie pies are best within 2 days, but they will keep up to 4 days. Store in a single layer airtight at room temperature.
1. Preheat the oven to 350°F / 175°C, with racks in the upper and lower thirds. Line two baking sheets with parchment paper.
2. Make the cakes: In the bowl of a stand mixer fitted with the paddle attachment (or in a large bowl, using a hand mixer), cream the butter, brown sugar, and granulated sugar on medium-low speed until light and fluffy, 4 to 5 minutes.
3. Add the egg and mix until well incorporated, 1 to 2 minutes. Scrape the bowl well. Beat in the vanilla, about 30 seconds.
4. In a medium bowl, whisk together the flours, baking powder, baking soda, and salt. Add one third of the flour mixture to the wet ingredients, mixing on low speed just until incorporated, about 1 minute. Add 120 g / ½ cup of the buttermilk and mix on low speed until fully incorporated, about 1 minute. Repeat, alternating between the flour mixture and the remaining buttermilk, until the ingredients are uniformly incorporated and the batter is smooth.
5. Use a #30 / 2-tablespoon scoop to portion the batter onto prepared baking sheets—stagger the cakes about 2 inches apart. Bake the cakes, rotating the sheets from front to back and top to bottom at the halfway mark, until lightly golden at the edges and the centers spring back lightly when touched, 12 to 15 minutes. Cool the cakes completely on the baking sheets.
6. Make the marshmallow crème: If you have a stand mixer with two bowls to go with it, fit the mixer with the whisk attachment, combine the butter, peanut butter, vanilla, and salt in one of the bowls, and mix on medium speed until smooth and well combined; remove the bowl from the mixer stand. Or use a hand mixer or a spatula or wooden spoon to blend the mixture in a large bowl. Set aside.
7. In a small saucepan, combine the granulated sugar, corn syrup, and water and bring to a boil over medium heat. Attach a candy thermometer to the side of the pan. As the mixture heats, you can stir to help the sugar dissolve, but stop stirring as soon as it comes to a boil. Continue cooking the sugar syrup, without stirring, until the thermometer reads 240°F / 115°C.
8. While the syrup cooks, whip the egg whites on low speed in the bowl of a stand mixer fitted with the whisk attachment (or in a large bowl, using a hand mixer) until lightly foamy, 1 to 2 minutes.
9. When the syrup reaches 235°F / 113°C, raise the mixer speed to high—the idea is to have the whites at soft peaks when it’s time to add the syrup. Cook the syrup until it reaches 240°F / 115°C.
10. With the mixer running, gradually add the syrup to the egg whites in a slow stream, then continue whipping until the meringue is thick and glossy and holds medium peaks, 5 to 7 minutes.
11. Temper (lighten) the peanut butter mixture by adding about one quarter of the meringue to it and folding thoroughly to combine (see for more about tempering). Then add the remaining meringue in three batches, folding very gently just until evenly incorporated.
12. Assemble the whoopie pies: Gently transfer the crème to a disposable pastry bag fitted with a large plain tip (such as #803; see Pastry Tips), or just snip a ½-inch opening at the tip of the bag after filling it. Put the jam in another pastry bag and snip a ¼-inch opening at the tip (you can also use a #60 / 1-tablespoon scoop or a tablespoon measure for the jam).
13. The cakes should all be roughly the same shape/size, but if you like, you can go through and pair each one up with its best match. Turn half of the cakes over. Pipe a thick ring of peanut butter crème around the edge of each overturned cake, about ¼ inch from the edge. Pipe/scoop about 8.5 g / 1 heaping tablespoon of jam into the center of each peanut butter ring, then top with the plain cakes. Press gently to “flood” the crème out to the edges.
✻ Why It Works
Despite their adorable name, whoopie pies are actually little cakes. The right amount of baking powder helps the batter rise in the oven before it spreads too much, resulting in soft cookie-like cakes. A light, airy filling (hello, marshmallow crème) is the perfect complement, providing moisture but still substantial enough to bite through.
★ Pro Tip
Surrounding a runny filling (like jam, jelly, or curd) with a piped ring of frosting helps contain it, so there’s no worry that the filling will spill out the sides.