Whoopie Pie Baking Video

Ingredients: 

Chocolate Caky Cookies

• 1 3/4 cup All-purpose Flour
• 1 cup sugar
• 2/3 cup cocoa powder
• 1/2 tsp salt
• 1 tsp baking powder
• 1/4 tsp baking soda
• 3/4 cup unsalted butter, room temperature (if your butter is cold, pop it in the microwave for 10 seconds at a time, until you can press into the butter and leave an indentation, but it's not melted)
• 1 egg large, room temperature
• 1/4 cup buttermilk (if you don't have buttermilk, you can use 1/4 cup milk + 1/2 tsp cream of tartar)
• 2 TBS milk
• 1/4 + 1TBS cup coffee

• 5 egg whites at room temperature (if your eggs are cold, place the whole egg/un-cracked in a dish with warm/hot water in it, for about 5 minutes)
• 2 cups unsalted butter at room temperature
• 1 2/3 cups granulated sugar
• 1/4 tsp salt
• 1 tsp vanilla extract (optional)

Instructions:

For the Cake

• Sift all the dry ingredients (the flour, cocoa powder, salt, baking soda and baking powder) into a large bowl, whisk together and set aside.
• Add the wet ingredients (egg, buttermilk, milk, coffee) to a medium bowl, whisk together.
• Cream the room temperature butter then add the sugar and continue to mix until light and fluffy.
• Add the dry and wet mixtures in a few alternating batches (adding a little at a time, totaling around 5 rounds) to the butter starting with the dry. Turn off the mixer when adding the ingredients. Mix until just combined.
• Use a cookie scooper or appx 2 tablespoons of batter, and put onto a baking sheet lined with parchment paper or a silicon mat. Wet your fingers with water and pat down any batter sticking out, and to flatten down the mounds a bit.
• Bake for about nine minutes at 375F, and set a side to full cool down. 

For the Filling

• Add egg whites, sugar and salt in a heatproof bowl, or a stand mixing bowl, and whisk together.
• Place the bowl over a small pot of simmering water (about 1-2 inches of water), to create a double boil effect. Make sure the water does not touch the bottom of the bowl.
• Whisk the egg whites occasionally as it warms up, and a bit more frequently once it starts to warm up. Heat the mixture until it reaches an internal temperature of 160ºF (using a digital or candy thermometer, or if you don't have one, carefully stick your finger inside the mixture, and when it's not grainy between your fingers, it's ready). 
• Transfer the bowl to a stand mixer, mix with a whisk attachment until you get room temperature glossy peaks. 
• Switch to a paddle attachment and while the mixture is running on low, add tablespoon sized dollops of room temperature butter making sure to let the butter incorporate before you add the next piece. If the mixture starts to look soupy and deflated, that's ok, just keep going slowly, adding the butter, until it's all added. As long as your meringue wasn't too warm when you started, this should magically come together and start to look like thicker, stable buttercream. If it never ends up stiffening up, just finish adding all your butter, as usual, and put the finished bowl in the fridge for 10 minutes, to cool down, and bring it back to the mixer to beat to the correct consistency. 
• Transfer the filling into a piping bag or to a ziplock bag.
• Pipe the buttercream onto the flat side of a caky cookie, and sandwich together with another cookie, so that both flat sides have the filling touching them. Enjoy!