recipe from joythebaker.com

 the Bit Fat Cookie book

makes 8 giant cookies 

1 1/2 cups all-purpose flour

1/2 teaspoon baking powder

1/4 teaspoon baking soda

1/4 teaspoon salt 

6 Tablespoons (3/4 stick) unsalted butter, at room temperature

1 cup sugar

1 teaspoon finely grated lemon zest

1 large egg

1 Tablespoon fresh lemon juice

1 teaspoon vanilla extract

1/2 cup buttermilk.

Lemon Cream Cheese Filling 

6 Tablespoons (3/4 stick) unsalted butter, at room temperature

6 ounces cream cheese, at room temperature

1 teaspoon vanilla extract

1 teaspoon finely grated lemon zest

2 Tablespoons lemon juice

2 3/4 cup powdered sugar 

Position a rack in the middle of the oven.  Preheat the oven to 350 degrees F.  Line two baking sheets with parchment paper and butter the paper.

Sift together the flour, baking powder, baking soda, and salt into a medium bowl and set aside.  In a large bowl, using an electric mixer on medium speed, beat the butter, sugar and lemon zest until smooth, about 3 minutes.  Stop the mixer to scrape the sides of the bowl as needed during the mixing.  Add the egg, lemon juice and vanilla, mixing until blended, about 1 minute.  The batter may look curdled.  On low speed, add half of the flour mixture, mixing just to incorporate it.  Mix in the buttermilk.  Mix in the remaining flour mixture just until it is incorporated and the batter looks smooth again.  

Drop heaping tablespoons (about 3 level Tablespoons each for a giant cookie) of dough onto the prepared baking sheets, spacing them about 3 inches apart.  Bake the cookies one sheet at a time until toothpick inserted in the center comes out clean and the tops feel firm, about 12 minutes.  With the exception of a time line at the edges, the tops of the cookies should not brown.  Cool the cookies on the baking sheets for 10 minutes, then use a wide metal spatula to transfer them to a wire rack to cool completely.   

To make the filling-

In a large bowl, using an electric mixer on low speed, beat the butter, cream cheese, vanilla, lemon zest and lemon juice until thoroughly blended and smooth, about 1 minute.  Add the powdered sugar and mix until smooth.  If the filling is too soft to hold its shape, chill it in the refrigerator for about 30 minutes.  

Turn half of the cookies bottom side up.  Leaving a 1/4-inch plain edge, use a thin metal spatula to spread each one with about 1/4 up of filling.  Gently press the flat bottoms of the remaining cookies onto the fillings.  

Wrap each cookie in plastic wrap and refrigerate for at least 1 hour.  Serve cold.  The wrapped cookies can be stored in the refrigerator for up to 4 days.