I firmly believe age is only a number and some people will always be young at heart. If my unwavering love of candy is any indication, I’m still hanging out around age 8. You can imagine, then, my extreme excitement at the idea of a cookie incorporating Pop Rocks. I am easily amused and have been fascinated with Pop Rocks since I was a child. The crazy snap-crackle-pop feeling of them in your mouth is weird and fun at the same time. The idea of using them in a dessert to represent some of the firecracker fun of the Fourth of July is inspired – I love it!
The one drawback to the use of Pop Rocks is that they are time sensitive. As soon as you open the package you can hear them quietly crackling, and they begin to stick together a bit (or at least they did in my humid kitchen). The moisture of the frosting also melts them down slightly on contact. To be sure that they have maximum popping activity, I recommend adding the Pop Rocks just before serving. This would be a fun activity with kids, letting them add the Pop Rocks themselves before eating and enjoying. Or, if you would rather do something that can be made in advance, you could just use a mixture of red, white and blue sprinkles and call it a day.
Side note – You know the urban myth that eating Pop Rocks and drinking Coke at the same time will make you explode (or something)? I won’t lie, as a kid I was 99% sure it wasn’t true…but not sure enough to try it myself. Now I know better but still find the proposition intriguing, so I went ahead and tried it while I was making these cookies. Obviously I lived to tell the tale so it is apparently not as lethal as kids might believe, but man, it was a crazy party in my mouth!
Firecracker Whoopie Pies
Yield: about 24-30 sandwich cookies
For the cookies:
8 tbsp. unsalted butter, at room temperature
¾ cup sugar
1 large egg plus 1 large egg white
1 tsp. vanilla extract
2¼ cups all-purpose flour
1½ tsp. baking powder
¾ tsp. salt
½ cup milk
For the filling:
10 tbsp. unsalted butter, at room temperature
1¼ cups confectioners’ sugar, sifted
Pinch of salt
2 tsp. vanilla extract
1 tbsp. heavy cream
Red and blue Pop Rocks (about 3 packages of each)
White jimmies or other sprinkles (optional)
To make the cookies, preheat the oven to 350˚ F. Line two baking sheets with parchment paper or silicone baking mats. In the bowl of an electric mixer combine the butter and sugar. Beat on medium-high speed until light and fluffy, 2-3 minutes. Blend in the egg and egg white, scraping down the bowl between additions. Blend in the vanilla. In a medium bowl, combine the flour, baking powder, and salt; whisk to blend. With the mixer on low speed, beat in half of the dry ingredients, mixing just until incorporated. Mix in the milk. Beat in the remaining dry ingredients, just until incorporated.
Transfer the cookie batter to a pastry bag fitted with a large round tip (I used an Ateco #809). Pipe the batter into 1½-inch rounds onto the prepared pans, spacing them an inch or two apart. Bake 7-8 minutes, just until set. Let cool on the pan at least 10 minutes, then transfer to a wire rack to cool completely.
To make the filling, whip the butter on medium-high speed until smooth, about 30 seconds. Mix in the confectioners’ sugar and salt, and beat on medium-high speed until smooth, 1-2 minutes. Mix in the vanilla and heavy cream on low speed just until incorporated, then increase the speed to medium-high and whip for 4 minutes, stopping and scraping down the sides of the bowl once or twice. Transfer to a pastry bag fitted with a plain tip.
To assemble the cookies, match them up in pairs by size. Pipe a dollop of filling onto the flat side of one cookie of each pair, and sandwich the cookies together, pushing the filling to the edges. Place the Pop Rocks in small bowls (mix in white jimmies for contrast, if desired). Dip the edges of the cookies into the Pop Rocks so that they adhere to the frosting. Serve immediately.