Buttermilk Cookies
From Gourmet, January 2008

3 cups all-purpose flour
1 teaspoon grated lemon zest
1/2 teaspoon baking soda
1/2 teaspoon salt
1 1/2 sticks unsalted butter, softened
1 1/2 cups granulated sugar
2 large eggs
1 teaspoon pure vanilla extract
2/3 cup well-shaken buttermilk

For Glaze
1 1/2 cups confectioners sugar
3 tablespoons well-shaken buttermilk
1/2 teaspoon pure vanilla extract

1. Preheat oven to 350°F with rack in middle. Butter 2 large baking sheets.
2. Whisk together flour, zest, baking soda, and salt.
3. Beat together butter and sugar in a large bowl with an electric mixer until pale and fluffy. Add eggs 1 at a time, beating well after each addition, then beat in vanilla. Mix in flour mixture and buttermilk alternately in batches at low speed, beginning and ending with flour mixture, until smooth.
4. Drop level tablespoons of dough about 1 1/2 inches apart onto baking sheets. Bake, 1 sheet at a time, until cookies are puffed and edges are golden, 12 to 15 minutes per batch. Cool cookies on sheets 1 minute, then transfer cookies to racks.
5. Whisk together all glaze ingredients and brush onto tops of warm cookies. [Note, you should sift the confectioners sugar first.]
6. Let stand until cookies are completely cooled and glaze is set.

Note: After I glazed 2/3 of the cookies with the vanilla glaze, I whisked cocoa powder in to the glaze (you can do this to taste) and used that on the rest of the cookies.