Just pulled this from the lovely Cupcakes and Cashmere. Stupid easy if you have a food processor. When you first make them, the wafers will seem really hard and the cream might squish out a bit, but over time, the wafers soften ever so slightly and they're PERFECT. I prefer keeping them in the fridge, but they will hold up in the cupboard.
**Note about assembly** This recipe says that you need a piping bag in order to put the put the sandwiches together. I've done without it and it's fine. The piping bag just ensures that you get 'perfect' looking edges, but I just do it with with a teaspoon. I find twisting the top and the bottom in opposite directions as you assemble helps the cream spread out evenly throughout the cookie.
Makes 25 to 30 sandwich cookies >>> I found it only made 20ish.
For the chocolate wafers:
1 1/4 cups all-purpose flour
1/2 cup unsweetened Dutch process cocoa
1 teaspoon baking soda
1/4 teaspoon baking powder
1/4 teaspoon salt
1 to 1 1/2 cups sugar [see recipe note] >>> I stick with 1 cup and they are plenty sweet.
1/2 cup plus 2 tablespoons (1 1/4 sticks) room-temperature, unsalted butter
1 large egg
For the filling:
1/4 cup (1/2 stick) room-temperature, unsalted butter
1/4 cup vegetable shortening
2 cups sifted confectioners’ sugar
2 teaspoons vanilla extract >>> I've used up to 1 1/2 tablespoons of the real stuff
1. Set two racks in the middle of the oven. Preheat to 375°F.
2. In a food processor, or bowl of an electric mixer, thoroughly mix the flour, cocoa, baking soda and powder, salt, and sugar. While pulsing, or on low speed, add the butter, and then the egg. Continue processing or mixing until dough comes together in a mass.
>>>NOTE>>> Resist the temptation to chill the batter. I know it makes it easier to handle when you're trying to roll it into balls, but chilled batter will keep the cookies from spreading as much as they should. For these, you're better off with thinner, crispier cookies rather than taller, chewier cookies (speaking from experience).
3. Take rounded teaspoons of batter and place on a parchment paper-lined baking sheet approximately two inches apart. With moistened hands, slightly flatten the dough. Bake for 9 minutes, rotating once for even baking. Set baking sheets on a rack to cool.
4. To make the cream, place butter and shortening in a mixing bowl, and at low speed, gradually beat in the sugar and vanilla. Turn the mixer on high and beat for 2 to 3 minutes until filling is light and fluffy.
5. To assemble the cookies, in a pastry bag with a 1/2 inch, round tip, pipe teaspoon-size blobs of cream into the center of one cookie. Place another cookie, equal in size to the first, on top of the cream. Lightly press, to work the filling evenly to the outsides of the cookie. Continue this process until all the cookies have been sandwiched with cream. Dunk generously in a large glass of milk.