Homemade Oreos

Chocolate Ice Box Cookies
Makes about 45 cookies
 2 cups unbleached all purpose flour
1/4 cup Dutch processed cocoa powder
1/2 teaspoon salt
16 tablespoons (2 sticks) unsalted butter, softened but cool
3/4 cup granulated sugar
1/2 cup confectioners sugar
2 ounces melted and cooled semisweet chocolate
2 large egg yolks
2 teaspoons vanilla

1. Whisk together the flour, cocoa powder, and salt in a medium bowl; set aside.
2. Either by hand or with an electric mixer, beat the butter and sugars at a medium speed until light and fluffy, 1 to 1 1/2 minutes. Scrape the sides of the bowl with a rubber spatula. Add the yolks, melted chocolate, and vanilla and beat until incorporated, 15 to 20 seconds. Scrape the bowl with a rubber spatula. Add the dry ingredients and mix at a low speed until a dough forms and is thoroughly mixed, about 25 to 30 seconds.
3. The dough will be soft but should not be sticky. If the dough is sticky, chill for 10 to 15 minutes. Divide the dough in half. Working with one half at a time, roll the dough on a clean work surface into a log measuring about 6 inches long and 2 inches thick. Wrap each log in plastic wrap and refrigerate for at least 2 hours, or up to 3 days (Dough can be frozen up to 1 month, wrap logs in plastic and and then foil before freezing).
4. Adjust the oven racks to the upper and lower middle positions. Heat the oven to 325 degrees. Line 2 large baking sheets with parchment paper or spray them with nonstick cooking spray.
5. Unwrap the logs one at a time and with a sharp knife, cut the dough into 1/4 inch thick slices. Place the slices on the prepared baking sheets, spacing them 1/2 to 1 inch apart.
6. Bake until edges begin to brown, about 14 minutes, rotating the baking sheets front to back and top to bottom halfway through the baking sheets for 2 minutes, then transfer to a wire rack with a wide metal spatula.

Filling
12 Oz. White chocolate
1/4 cup Sour Cream

1. Completely melt White Chocolate on a double boiler on the stove.
2. Add in sour cream and stir until combined.
3. Let icing cool, can place in the refrigerator for faster cooling (about 20-30 min).

Filling the Cookies
1. Using a small spoon, add a dollop of frosting to the center of one cookie. (too much filling will cause the Oreos to overflow).
2. place another cookie on top of the cookie with the filling. Gently press the two together.

(Recipe adapted from Baking Illustrated Sandwich cookies.)

Notes: I found that one recipe of filling was waaay more than I needed to fill one recipe of Chocolate cookies. I would suggest either making 2 batches of chocolate ice box cookies or halving the recipe of the filling to avoid having extra.