-
1
Make the filling: Preheat the oven to 350.
-
2
Line 2 baking sheets with parchment paper.
-
3
Make the filling: In a large bowl, using an electric mixer, beat the butter with the brown sugar and granulated sugar until smooth.
-
4
Add the melted chocolate and vanilla and beat until smooth.
-
5
In a small bowl, whisk the flour with the cocoa powder, baking soda and salt.
-
6
Add the dry ingredients to the bowl and beat at low speed just until incorporated.
-
7
Roll the dough between 2 sheets of parchment paper to a scant 1/4-inch thickness and refrigerate until firm, about 15 minutes.
-
8
Make the filling: Using a 2-inch round cookie cutter, stamp out as many rounds as possible and transfer to the baking sheets, 1 inch apart.
-
9
Gather the scraps and chill, with the cut-out rounds, for 10 minutes.
-
10
Reroll the scraps and stamp out more rounds.
-
11
Make the filling: Bake the cookies in the lower and middle thirds of the oven for about 10 minutes, until dry and set; shift the pans halfway through baking.
-
12
Transfer the cookies to a rack and let cool completely.
-
13
Make the filling: In a medium bowl, using an electric mixer, beat the butter with the chocolate malt powder at medium speed until light, about 3 minutes.
-
14
Add the vanilla and confectioners' sugar and beat at low speed just until combined.
-
15
Transfer the filling to a pastry bag fitted with a 1/2-inch plain tip.
-
16
Arrange half of the cookies on a work surface, bottom side up, and pipe a 1-inch mound of filling onto each.
-
17
Sandwich with the remaining cookies, pressing to spread the filling to the edges.
-
18
Serve.
