for the cookies

1. Preheat oven to 350.
2. Whisk together flour, baking soda, and salt in a bowl. Stir together buttermilk and vanilla in a cup.
3. Beat together butter and sugar in a large bowl with an electric mixer until pale and fluffy, about 3 minutes, then add egg, beating until combined well. Mix in flour mixture and buttermilk mixture alternately in batches at low speed (scraping down side of bowl occasionally), beginning and ending with flour mixture. Mix until smooth.
4. Spoon 1/4 cups of batter about 2 inches apart onto a buttered/silpat lined large baking sheet. Bake in middle of oven until tops are puffed and pale golden, and cookies spring back when touched, 15 to 17 minutes. Transfer to a rack and cool, about 5 minutes.

to make the icing

1. Stir together confectioners sugar, corn syrup, lemon juice, vanilla, and 1 tablespoon water in a small bowl until smooth. Transfer a little less than half of icing to another bowl and stir in cocoa, adding more water, 1/2 teaspoon at a time, to thin to same consistency as white icing.

to ice the cookies

1. Dip the flats of the cookies into the vanilla icing and allow to sit for a few minutes (while you’re icing the remainder, this should give it enough time to set up, or become hard). Take your cookies and line them up in long rows. Slowly pour your chocolate frosting over the cookies in a sweeping motion so that the chocolate icing covers half of the cookies.