Fluffy chocolate whoopie pies are two fluffy cakes with a delicious creamy vanilla cream cheese frosting sandwiched in between. This is the perfect chocolaty dessert to celebrate a birthday or take to a party, and the end result is delicious!
In a one cup measuring cup, add the lemon juice. Fill the cup the rest of the way with milk and set aside for 10-15 minutes to make buttermilk.
In a large mixing bowl with an electric mixer, or in the bowl of a standmixer, cream together 1/2 cup butter, the brown sugar, and granulated sugar.
In a small bowl, beat the egg with a fork and add it to the large bowl. Add 1 teaspoon of vanilla and lemon-milk mixture and mix all the ingredients well until they are combined.
In a medium bowl, combine the flour, cocoa, baking soda, and salt. Mix all the dry ingredients well, then add the dry ingredients to your wet ingredients and mix well until combined. The batter will be a little on the fudgy side.
On a baking sheet lined with parchment paper, place 2 tablespoons of batter for each cookie. Try to keep your whoopie pies in as much of a circle and even in size as you can. (A cookie scoop really helps to make the whoopie pies even, but most standard are 11/2 tablespoons. Expect to have a few more, slightly smaller whoopie pies!)
Bake in the oven for 11 to 12 minutes. Remove quickly from the pan as soon as you can and let the whoopie pies cool on a wire rack or clean kitchen towel.
Make The Cream Cheese Frosting
In a large mixing bowl with an electric mixer, or in the bowl of a stand mixer, whip 1/2 cup of butter for 5 minutes. Scrape down the sides of the bowl, then add the cream cheese and beat for 1 to 2 minutes more.
Scrape down the sides of the bowl and add the powdered sugar 1/2 cup at a time, mixing well between each addition. Add 1 teaspoon of vanilla and mix for 1 minute more.
Assemble The Whoopie Pies
Once cool, match up your whoopie pies in pairs so that they are as close in size and shape as possible. Fill an icing bag or zip-top bag with filling. Snip a medium hole in the end of your bag.
On the flat side of one of your whoopie pies, pipe filling around the outside edge as close to the edge as possible, then swirl in, filling into the center. Place a second whoopie pie on top. Roll the edge in sprinkles to decorate.
Whoopie pies come in lots of other flavors—like pumpkin, chocolate peanut butter, or even gingerbread. The fastest way to change the flavor is to roll the outside of the whoopie pies in candy cane bits, graham crackers, or other crushed-up candies. Or just change up your sprinkle color for whatever holiday you are celebrating.