1.The texture of these cookies depends on three things: not over-mixing, rolling the dough a full 1/4 inch thick, and baking just until done.
2. Preheat oven to 350 degrees.
Beat with an electric mixer: Unsalted butter Granulated sugar Dark brown sugar
Add and mix completely: Eggs Vanilla extract
Sift together, then add and mix just until completely incorporated: Flour Cocoa Salt Baking powder
Roll the dough out on a lightly floured counter to 1/4 inch thickness and cut, then transfer the cookies onto cookie sheets that have been lined with parchment paper or silicone liners.
If desired, use a paring knife to score a pattern on the cookies to resemble the pleats in a cupcake liner.
Bake 8 to 10 minutes, until the surface of the cookies looks completely dry and set. Let the cookies cool slightly on the sheets, then transfer to a wire rack to cool completely before frosting.
Fluffy White Frosting Makes enough to frost 18 cookies, or one 8 inch layer cake
This is a simple, basic egg white recipe that makes a glossy, fluffy frosting. Make sure your bowl and beaters are clean and grease free before whipping the egg whites. A standing mixer is helpful for this recipe; a hand-held mixer will take longer to whip the frosting fully.
Place in a small saucepan: 1 cup granulated sugar 1/3 cup water 1/4 teaspoon cream of tartar
Heat over medium heat, stirring to dissolve sugar, until the mixture is bubbling. Simmer for 1 minute.
While sugar mixture cooks, whisk with an electric mixer until foamy: 2 large egg whites 1 teaspoon vanilla
With mixer running, add hot sugar syrup to egg whites in a slow, steady stream.
Beat egg whites until very thick, glossy, and stiff, 7 to 10 minutes.
Spoon frosting into a pastry bag fitted with a star tip and pipe onto cookies.