Ingredients
1 c. dark chocolate, chopped
2/3 c. heavy cream
1 1/4 c. all-purpose flour
1/2 tsp. kosher salt
9 tbsp. butter, softened
1 1/4 c. powdered sugar
1 whole egg, plus 1 egg white
2 tsp. pure vanilla extract
1 tbsp. whole milk
Preparation
Step 1Adjust an oven rack to center position and preheat to 350°. Line 2 baking sheets with parchment paper.Step 2Make the ganache: Add chopped chocolate to a medium heatproof bowl. In a small pot, bring the cream to a low boil. Immediately pour the hot cream over the chocolate. Let sit for 2 minutes, then lightly whisk to create a smooth sauce. Set aside. (At this point the ganache will be quite loose. But by the time the cookies are cooled, it will be thick enough to pipe between the layers. If it’s still too loose, refrigerate it for 5 minutes and stir.)Step 3Make the cookies: In the bowl of a stand mixer fitted with the paddle attachment or in a large bowl using a hand mixer, cream together the butter and sugar on medium speed.Step 4In a small bowl, use a fork to break up the whole egg. Add the egg white and mix to combine. With the mixer running, add the eggs a little at a time, making sure that it is fully incorporated before adding the remaining eggs. Stir in the vanilla extract and milk.Step 5Using a spatula, fold in the flour to completely combine. Move the cookie batter to a piping bag fitted with a large round (1/2") tip.Step 6Pipe the batter directly on the baking sheets. They should be piped about 3” long and at least 1.5” apart from one another, as they will spread in the oven. Bake both sheets simultaneously for 15 minutes, rotating the pans at the halfway mark. Continue baking until cookies are golden brown at the edges. Transfer to a cooling rack.Step 7Fill the cookies: Once cookies are fully cooled, pipe or spoon a teaspoon of ganache between the cookies to make sandwiches. (Not too much or it will spill out the sides.) If you need to serve the cookies immediately, refrigerate 5 to 10 minutes to help the ganache set up.
Consistency in piping is key. Feel free to draw lines on the back of your parchment paper to use as a guide. And if one comes out less than perfect, just scrape it up and re-pipe it.
