SOK Bake Sale, Part 1: Chocolate-Passionfruit Whoopie Pies

10 Sep

I’ve been on something of a baking kick lately, thanks to a newfound sweet tooth coupled with actually having some events to bake for. (Even on my most dedicated sweets binge, I find it hard to finish a dozen cupcakes while they’re still fresh.) I wanted to bring something festive to a baby shower, but wanted to try my hand at something new, so I decided to make some whoopie pies. These have been something of a trend lately, though not as ubiquitous as cupcakes or macarons; it’s frosting sandwiched between two cake-cookies (basically, cake batter baked like a drop cookie). Though the classic combo is chocolate cake with vanilla frosting, à la Oreos or Ding Dongs, but any combination that you would use for a cake will work; pumpkin and red velvet are especially popular. I’ve been wanting to make something with passionfruit, and everyone loves chocolate, so chocolate and passionfruit it was.

The cake portion of the whoopie pies

First I baked the cake portion, using this recipe from Baked Explorations, via The Modern Domestic. I omitted both the hot coffee and the coffee powder and used extra buttermilk instead. The batter was sticky as the dickens (they don’t call it devil’s food for nothing), but they baked up beautifully—fluffy but not dry.

With the easy part out of the way, I turned my attention to the filling. Tradition calls for marshmallow fluff, which is fine for Ding Dongs but not if you’re baking from scratch. (Unless you’re also making the marshmallows, I suppose.) Plus, marshmallow fluff is incredibly expensive in Malaysia; I’d rather spend the cash on butter or something. I also ruled out “standard” buttercream, which is essentially butter whipped with icing sugar, because I felt like it would be too heavy, and it doesn’t hold well in Malaysia’s tropical climate. So I decided to try my hand at Swiss meringue buttercream.

SMBC, as it’s known to baking aficionados (who presumably don’t want to spell meringue over and over), adds a cooked meringue to the butter, which both stabilizes the frosting (i.e. not melting all over the place) and lightens the texture. It’s the kind of frosting you get at higher-end bakeries. My baking guru friend recommended Martha Stewart’s recipe and assured me that it wasn’t difficult at all. (Then again, she’s also the kind of person who makes marshmallows from scratch.) And she’s right: SMBC isn’t hard, in the way pie crust or biscuits are. But it is time-consuming. I really missed my stand mixer, although I at least had a handheld version. Growing up, we didn’t have either, and I remember how tedious it was whipping egg whites by arm power alone. 

I got through the initial meringue stage of SMBC with no problems except a sore arm. But tragedy struck when I started adding butter:

Swiss meringue buttercream is not supposed to look like curdled milk.

Luckily, SMBC is a forgiving frosting. Thanks to Google, I was able to figure out how to fix my “broken” frosting, resulting in this:

Fluffy success!

Now for the passionfruit. I don’t have any photos of the fruit itself—I used pulp that I already had frozen—but here’s a photo of the strained juice next to the pulp to give you an idea of the ratio:

Strained juice on the left, seeds on the right. I’d say it’s about a 1:1 ratio.

For two cups of frosting, I used about five whole passionfruits. Of course, you could always use concentrate/nectar or passionfruit curd instead, but I’m not about to go through the hassle of making curd just for the sake of putting it in frosting, when the juice does the job.

Finally, at about midnight, I put my fluffy, perfect passionfruit SMBC in the fridge, since I figured assembling whoopie pies in advance would be a no-no. I took it out in the morning and started beating it to soften the frosting up. It turned back into a curdled mess. “That’s OK,” I thought, “I’m sure it’ll come back together if I just keep beating.” Nope. In fact, it just got worse: little blobs of butter in a yellow-gray liquid. By this time, I had only an hour before I was supposed to be at the baby shower (a surprise baby shower, so I couldn’t be late), not nearly enough time to make new frosting. I googled. I put the frosting over simmering water. I refrigerated the frosting. Nothing. Finally, after I dried my tears, I started hand-whisking out of desperation. And lo and behold…

The final product!

Miraculously, the frosting came back together into a fluffy emulsion. (I’m sure there’s some sort of scientific explanation involving the speed of the beaters and kinetic energy and so forth. Geeky SOK readers, have at it in the comments.) And the whoopie pies ended up being delicious: moist little chocolate cakes with a tangy, fruity, and above all, light filling.

So was SMBC worth all the angst? I am going to say yes. It has a texture like ice cream, but not cold; for frosting haters, it will change your view of the baked goods universe forever. Plus it holds like a dream: I had these babies out at room temperature in Malaysia (which is about 80 degrees F) for two hours and there was no melting or goopiness. The challenge now is to figure out what to do with all those egg yolks, especially since I can’t use them for mayonnaise.

*If you’d like to try your hand at SMBC, I found the posts at Confections of a Foodie Bride and Whisk Kid to be invaluable. Thank you for saving my frosting!


2 Responses to “SOK Bake Sale, Part 1: Chocolate-Passionfruit Whoopie Pies”


  1. SOK Bake Sale, Part 2: Pandan Cupcakes with Gula Melaka Frosting « Straight Out of Kampung - September 12, 2012

    […] topped the cupcakes with gula melaka Swiss meringue buttercream, putting the previous day’s lessons into action. When my frosting started curdling, I walked away and Skyped my husband and his family; […]

  2. Green Tea Oreo “Soft Cookies” « Straight Out of Kampung - November 8, 2012

    […] can’t remember where I heard about this, but apparently Oreo is trying to cash in on the whoopie pie fad by introducing a variation they’re calling “soft cookies.” They’re also […]

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: