http://cookiepiebklyn.blogspot.com/, and you find that recipe and so many more.
Preheat your oven to 350.
12 Tbsp. unsalted butter, softened
2 1/2 cups confectioners' sugar
7/8 cup egg whites (from about 6 large eggs)
2 Tbsp. vanilla extract2
Tbsp. lemon extract [I omitted]
1 1/2 cups all-purpose flour
In a mixing bowl, using an electric mixer, cream the butter with a paddle attachment, then mix in the sugar. Add the egg whites gradually and then mix in the vanilla extract. Add the flour until just incorporated.
With a small (1/4-inch) plain tip, pipe 1-inch sections of batter onto a baking sheet, spacing them 2 inches apart. Although I will admit, I did not have a tip, so I just used the bag.
Bake for 10 to 12 minutes, or until light golden brown around the edges. Let cool on the pan.
8 oz. semisweet chocolate
In a small saucepan over medium flame, scald cream. Pour hot cream over chocolate in a bowl. Whisk to melt chocolate and blend well. Set aside to cool. The ganache will thicken as it cools. Now pair up the cookies to match as best as possible. Spread with cooled ganache and sandwich together.