CAKE (using the reversed creaming method)

1. Preheat oven to 350 degrees. Generously grease a 9 x 13 cake pan and set aside.
2. To the large bowl of a stand mixer, using the paddle attachment, add the cake flour, baking soda, baking powder, salt, and 1 cup of the granulated sugar. Turn the mixer to low and thoroughly combine the ingredients. On medium speed, add 1/2 of the sour cream, followed by the butter, adding it one tablespoon at a time. Stop and scrape down the sides and bottom of the bowl halfway through. Add the remaining sour cream, oil, and vanilla and mix on medium speed until the batter becomes light and airy about 2 minutes.
3. In a separate mixing bowl, using the whisk attachment, whip the egg whites and cream of tartar together on medium-high speed until soft peaks form. Reduce speed to medium-low and gradually add the remaining 1/2 cup of granulated sugar. Return the mixer to medium-high speed and mix until stiff shiny peaks form. Do not overbeat. As soon as the egg whites look stiff and shiny, stop beating. If they begin to look dry, you’re overbeating them.   
4. Using a spatula, gently fold the beaten egg whites into the batter, one third at a time. Add the Oreo cookie pieces in with the last addition of egg whites and gently fold until you see a few streaks of egg whites left. 
5. Transfer the batter to the prepared cake pan and bake for approximately 35 to 40 minutes, or until a toothpick inserted into the center comes out clean. Transfer the cake to a wire rack to cool completely, before frosting.

WHIPPED CREAM CHEESE FROSTING

1. Make the frosting: Add the cream cheese to the bowl of a stand mixer, fitted with the whisk attachment (or use a hand mixer). Beat the cream cheese on high speed until it’s very smooth and creamy, and free of any lumps. Stop and scrape down the sides and under the whisk attachment halfway through. Add the powdered sugar, and vanilla and beat on medium speed for about 2 minutes, stopping halfway through to scrape down the side and bottom.
2. In a separate mixing bowl, using the whisk attachment, beat the whipping cream on low speed until it no longer splatters. Turn the mixer to high and beat until the whipping cream forms stiff peaks.
3. Using a spatula, gently fold the whipped cream into the cream cheese mixture, followed by the cookie pieces. 
4. Frost the cake: Using an offset spatula, spread the frosting over the cooled cake. There’s plenty of frosting. Decorate the top with additional cookie pieces if desired.