Makes 12 Cookies

Twelve cookies doesn’t sound like much, but these cookies are huge. Youll get neater cookies if you spread on the vanilla glaze first.

COOKIES

1 3/4 cups all purpose flour

1/2 tsp baking powder

1/4 tsp baking soda

1/8 tsp salt

10 tbsp unsalted butter,softened

1 cup granulated sugar

1 large egg

2 tsp vanilla extract

1/3 cup sour cream

GLAZE

5 cups confectioners sugar,sifted

7 tbsp whole milk

2 tbsp corn syrup

1 tsp vanilla extract

1/2 tsp salt

3 tbsp Dutch-processed cocoa powder,sifted

1.FOR THE COOKIES: Adjust oven racks to upper-middle and lower -middle positions and heat oven to 350 degrees. Line 2 baking sheets with parchment paper. Combine flour,baking powder,baking soda,and salt in a bowl.

2. Using stand mixer fitted with paddle, beat butter and sugar on medium high speed until pale and fluffy, about 2 minutes.Add egg and vanilla and beat until combined. Reduce speed to low and add flour mixture in 3 additions of sour cream, scraping down bowl as needed. Give dough final stir by  hand.

3. Using greased 1/4 cup measure, drop cookie dough 3 inches apart onto prepared baking sheets. Bake until edges are lightly browned, 15 to 18 minutes, switching and rotating sheets halfway through baking. Let cookies cool on sheets for 5 minutes, then transfer to wire rack to cool completely, about  1 hour.

FOR THE GLAZE

Whisk sugar, 6 tbsp milk, corn syrup,vanilla, and salt together in bowl until smooth. Transfer 1 glaze to small bowl; reserve. Whisk cocoa and remaining 1 tbsp milk into remaining glaze until combined.

Flip cookies after they are baked so that the flat bottom,which is easy to glaze, becomes the top.

Working with 1 cookie at a time,  spread 1 tbsp vanilla glaze over half of underside of cookie. Refrigerate until glaze is set, about 15 minutes. Cover other half of cookies with 1 tbsp chocolate glaze and let cookies sit at room temperature until glaze is firm. at least 1 hour. Serve.