6 Tbsp butter, softened
2/3 cup granulated sugar
1/3 cup cocoa powder (I use Hershey's)
1/4 tsp baking powder
1/8 tsp salt
1 egg
2/3 cup all-purpose flour
1 recipe for filling (below)
1. In a bowl, with a mixer, beat the butter on medium for 1 minute. Add the sugar, cocoa, salt, and baking powder. Beat until combined, scraping bowl as needed. Beat in egg. Beat in flour until dough comes together.
2. Spoon dough onto a large piece of plastic and wrap into an 8-inch line. Wrap the long sides of the plastic tightly over the dough. Roll dough gently over the countertop while twisting the ends until it is a smooth, uniform log approximately 1 3/4 inches in diameter. Freeze for 1 1/2 hours until it is firm enough to slice. (Or chill for 4 to 6 hours.)
3. Preheat oven to 325 degrees F. Line 2 cookie sheets with parchment paper. If necessary, reshape log to make it evenly round. Using a sharp knife, cut log crosswise into 1/8-inch-thick slices. Place slices 1 inch apart on prepared cookie sheets.
4. Bake until edges are firm, 12 minutes. Cool on cookie sheet 2 minutes, then remove and transfer cookies to wire rack. When completely cool, fill with filing of your choice.
I used a butter-powdered-sugar-vanilla and vanilla cookie wafer and crushed almonds filling. I didn't have any freeze-dried raspberries on hand. But the original recipe has a raspberry filling. I think as long as you use butter and powdered sugar, you could add whatever you'd like.
Raspberry Cream Filling Recipe:
In a medium bowl beat 1/2 cup softened butter with a mixer on medium until creamy, 1 minute. Beat in 1 cup powdered sugar and 1/2 tsp. vanilla. Add 2 to 4 Tbsp. very finely crushed freeze-dried raspberries. Add more powdered sugar to form the consistency you like. Pipe or spread the mixture evenly onto the bottoms of half the cookies, 2 tsp. each, and then top each bottom with a cookie, bottom side down onto the filling. Gently press together. Makes 18 sandwich cookies.
