from the Dahlia Bakery Cookbook
for the cookie filling-
-6 tbsp unsalted butter
-1 cup toasted, cooled, and chopped pecans
-3/4 cup powdered sugar
-1 1/2 tsp pure vanilla extract
-1 tsp kosher salt
for the cookies-
-3/4 cup plus 1 tbsp all-purpose flour
-1/4 cup plus 2 tbsp unsweetened cocoa powder (I used dark)
-1/4 tsp baking soda
-1/2 cup plus 1 tbsp (1 stick plus 1 tbsp) unsalted butter, softened
-3/4 cup plus 2 tbsp granulated sugar
-1 large egg at room temperature
-1/4 cup toasted, cooled, and finely chopped pecans
-1 tsp pure vanilla extract
-1/2 tsp kosher salt
1. To make the filling, put the butter (6 tbsp) in a small saucepan over medium to medium-high heat. Allow butter to melt and then continue to cook, stirring constantly, until butter begins to brown and smell nutty (about 3 minutes or more). As soon as butter is a dark golden brown, remove it from the heat and pour it into a small bowl (butter burns quickly!).
2. In the bowl of a food processor, add the brown butter, pecans (1 cup), powdered sugar, vanilla extract, and salt. Pulse until a thick paste forms. Put the filling in a small bowl, cover, and chill while you make the cookies.
3. To make the cookie dough, sift the flour, cocoa, and baking soda in a bowl and set aside.
4. Beat butter with sugar, creaming for 3 minutes or until pale and fluffy. Add the egg and beat to incorporate. Mix in the pecans, vanilla, and salt.
5. Add the dry ingredients on low speed in 3 or 4 additions, mixing just until combined (don't overmix!). Chill dough for at least 1 hour before using.
6. Preheat oven to 375F. Drop dough (about 2 tsp in size) on parchment-lined baking sheets, about 1 inch apart. Bake pans for 7 minutes, or until cookies are cooked through and beginning to set. Don't open the door while they are baking. Allow cookies to cool for 10 minutes before transferring to a wire rack.
7. Cool cookies completely before filling. Remove filling from fridge to soften. To make a cookie sandwich, spread about 2 tsp of filling on the flat (bottom) side of one cookie. Top with a second cookie, pressing gently, to form a sandwich. Repeat with remaining cookies and filling.