My parents have a second freezer in the basement, between the washing machine and the wrapping paper. It’s for the essentials: summer berries from the garden, toaster waffles, and a seemingly endless supply of Girl Scout cookies. Sounds like a pretty good menu for the apocalypse, right?
I’m not sure if it was a product of having three daughters in the program or of having countless co-workers with enrolled offspring, but my parents take stocking these cookies very seriously. I didn’t realize until college that Thin Mints and Trefoils are a seasonal indulgence for most people, and the appearance of the brown or green uniforms in front of every grocery store means the end of a year-long hiatus. But the good kinds still run out first, and the best kind is obviously Tagalongs (Peanut Butter Patties to the unimaginative folks on the east coast). So to compensate in the off-season and to celebrate the birthdays of peanut-butter-chocolate lovers everywhere, we have this cake to remind us of the most important Girl Scout cookies even when the freezer has run out.
We start with a peanut butter cake. Already this is heading good places. Top it up with some ganache (always a good idea), crumbled shortbread cookies (I told you we’d put cookies in a cake!), another layer of cake (oh boy!), and more ganache on top. Make sure you incorporate naptime into any post-cake plans.
One final note on the cake: the first time I made this, it was for a coworker’s birthday and I didn’t have all of the ingredients for ganache while I was baking the night before. So I stopped at the store on the way and showed up at work with two cake layers, shortbread cookies, chocolate, heavy cream, a whisk, and a frosting spatula in my bag–on my bike. It may have been one of those “some assembly required” situations.
Creaming (peanut) butter
The first step for this recipe is pretty standard for a cake: cream together butter and sugar. Except in this case, it’s peanut butter–there actually isn’t any butter at all in the cake. So we beat the peanut butter with sugar and some oil, then proceed as usual.
Creaming the fat (butter or shortening) together with the sugar is an important beginning for many cakes, playing a role in the cake’s rising. In fact, for traditional pound cakes, beating the butter and sugar together shoulders the whole burden of leavening, as there isn’t any baking powder or soda at all. The mixing motion plus the tiny, sharp-edged sugar crystals introduces air pockets into the butter. These will expand as the air heats during baking, lifting and lightening the finished cake. Cakes that also have baking powder or soda will rise even more: the leaveners react during baking to produce carbon dioxide, which fills and broadens those miniscule holes in the butter.
You need a solid fat for this to work. Beating oil and sugar might be fun for you, but it won’t do much for your cake: the individual molecules are slippery enough that it’s a liquid, which means they can’t hold those air pockets that butter can. But what about a non-traditional solid fat? Peanut butter is solid! Although this recipe also relies on baking powder and soda, creaming the peanut butter and sugar at the beginning starts the leavening process off right.
Peanut butter cake, shortbread cookies, and ganache… what’s not to love? Make the shortbread (recipe here) ahead of time to simplify the process, or you can buy them to make your life easier (I won’t tell!). This cake is perfect for those people who can’t enough of peanut butter and chocolate or any Girl Scouts in your life.
Yield: 2-layer 9-inch cake
For the cake:
3 c. flour
4 t. baking powder
1 t. baking soda
1 t. salt
½ c. vegetable oil
2/3 c. creamy peanut butter
¾ c. brown sugar
¾ c. white sugar
2 t. vanilla
1 ½ c. buttermilk
For the ganache:
12 oz. bittersweet chocolate
1 ½ c. heavy cream
About 10 shortbread cookies (recipe here)
Make the cake layers: preheat oven to 350 degrees F. Grease and flour two 9-inch cake pans.
Sift the dry ingredients together.
In a separate bowl, use an electric mixer to cream the oil, peanut butter, and both sugars until smooth and fluffy. Add the eggs one at a time, then mix in the vanilla. Add the flour mixture in three additions, alternating with the buttermilk. Begin and end with the flour. Beat just until incorporated.
Pour the batter into the prepared pans. Bake for 30 minutes or until the top springs back when touched. Let the cakes cool in the pan for 10 minutes, then remove them from the pan to cool completely.
Make the ganache: melt the chocolate over a double boiler. Slowly whisk in the cream, a little at a time, until the mixture is smooth and holds its shape. Let come to room temperature before frosting.
Assemble the cake: place one cake layer on the serving plate. Cover the top with a layer of ganache, then bite-size shortbread cookie pieces, then more ganache. Add the top layer of cake. Frost the top and sides with ganache. Garnish with peanut butter and shortbread cookies.