Thousand Layer Chocolate Chip Cookies

I originally was a bit intimidated by this recipe from Sarah Copeland's The Newlywed Cookbook since it was featured on Martha Stewart's show earlier this year. Of course she tries to make everything on the show look easy, but it isn't always! This recipe is not difficult, but you do have to invest some time with the preparation of the layers and refrigeration of the dough. The result is worth it, though! The cookies are soft on the inside with crispy edges, and there's plenty of chocolate! It's what every chocolate chip cookie should be. I kept the dough in the refrigerator over the weekend and just made a few after dinner each night (and two for a Sunday afternoon snack!).


The recipe from the cookbook is below. Next time I may do 1 cup of brown sugar and 1/2 cup of granulated sugar instead. I did not do the egg wash or sprinkle with fleur de sel. I used semi-sweet chocolate chips instead of the bittersweet chocolate. This is my entry for AlphaBakes hosted on The More Than Occasional Baker this month. What a fun challenge! 

Ingredients
1 cup (2 sticks) unsalted butter, room temperature
3/4 cup packed dark-brown sugar
3/4 cup granulated sugar
4 large egg yolks, room temperature
1 teaspoon pure vanilla extract
2 1/4 cups all-purpose flour, plus more for work surface
3/4 teaspoon baking soda
3/4 teaspoon fine sea salt or table salt
9 ounces bittersweet chocolate
1 large egg, lightly beaten
1/4 teaspoon fleur de sel (optional)

Instructions
Preheat oven to 375 degrees. Line two baking sheets with parchment paper; set aside.
In the bowl of an electric mixer fitted with the paddle attachment, cream together butter and both sugars on medium-high speed until light and fluffy, about 3 minutes. Beat in egg yolks, two at a time; add vanilla and mix to combine.
In a large bowl, whisk together flour, baking soda, and salt. With the mixer on low, add flour mixture; mix until just combined. Scrape down sides of bowl and mix to combine.
Divide dough into three equal portions. Wrap each portion with plastic wrap and transfer to refrigerator; let chill for 30 minutes. Meanwhile, using a serrated knife, coarsely chop chocolate into thin shards. Set aside.
Unwrap one portion of chilled dough and place on a lightly floured work surface. Sprinkle with half the chocolate and top with a second portion of chilled dough. Sprinkle with remaining chocolate and top with remaining portion of dough.
Lightly dust with flour and gently roll out dough to a 9-by-6-inch rectangle, about 1 1/2 inches thick. Using a 2-inch-round cutter, cut out 10 rounds of dough. Gather scraps and lightly pat into another 1 1/2-inch-thick rectangle and cut out remaining cookies. Place on prepared baking sheets about 3 inches apart and brush with beaten egg. Sprinkle with fleur de sel, if desired.
Transfer cookies to oven and bake until cookies are set, 12 to 15 minutes, switching baking sheets from top to bottom halfway through baking. Let cookies cool slightly on baking sheets, about 3 minutes, before transferring to a wire rack to cool completely. Cookies can be stored in an airtight container for up to 4 days.
Yields 1 dozen.