Our sitter said this was the favorite cake she's tried at our house ... and she's tried quite a few.
Oreo Cake
1 cup plus 2 Tbsp. butter, room temperature
1 1/2 cups sugar
3 cups flour
1/2 tsp. baking soda
1 1/4 tsp. baking powder
1/2 tsp. salt
5 egg whites
2 tsp. vanilla
3/4 sour cream, room temperature
2/3 cup whole milk, room temperature
15 whole Oreo cookies, center creams removed
Chocolate Sprinkles Buttercream
1 1/2 cups unsalted butter
6 cups powdered sugar
2 tsp. vanilla
Milk or cream to thin to desired consistency
2/3 cup real chocolate sprinkles, such as DeRuijter
Chocolate Ganache & Decorations
1/2 cup chocolate chips
1/4 cup heavy cream
6 whole Oreos
Preheat oven to 350°F. In bowl of electric mixer, beat the butter until creamy. Sprinkle in sugar gradually as you mix. Beat until light and fluffy.
In separate large mixing bowl, sift together dry ingredients.
In a 4-cup measuring cup, whisk together egg whites, vanilla, sour cream and milk.
Beat 1/3 of the dry ingredients into the butter mixture until just incorporated. Add in half the liquid mixture, and beat until combined. Add another 1/3 of dry ingredients, and then remaining liquid mixture. Finish with the flour mixture, and beat until fluffy, about 2 minutes.
Grease and flour three 8-inch round cake pans. Coarsely crush the Oreo cookies into the cake batter, and stir by hand to mix. Bake the cakes for 25 to 30 minutes or until the cake springs back when pressed in the center. Cool 10 minutes on wire racks before flipping out to cool completely on wire racks.
To make the frosting, beat the butter until creamy. Add powdered sugar, and beat until combined. Add vanilla, and mix well. Beat on medium, adding milk or cream 1 Tbsp. at a time until the mixture thins to piping consistency. Beat on high until the frosting turns almost white in color, about 4 minutes. Scrape down bowl, and beat again on high speed. Fold in the chocolate sprinkles. Set aside 2/3 cup of frosting to a piping bag fitted with a large open star tip.
Fill 2 of the cooled cake layers with about 1/2 cup of buttercream on each layer. Spread evenly, and stack them and place the third cake layer on top. Generously cover the cake with the remaining buttercream using an offset spatula. Chill the cake until the frosting firms, about 25 minutes. Using the reserved piping bag of frosting, pipe 6 large swirls on the top edge of the cake, evenly spaced. Chill the cake while you make the ganache.
In a medium microwave-safe bowl, combine the chocolate chips and heavy cream. Microwave on high for 1 minute. Allow the hot mixture to stand 2 minutes, and then whisk together until smooth. Let cool slightly. The mixture should be quite liquid and not thick before applying to the cake.
Spoon the ganache conservatively at the edges of the cake, and around the frosting swirls, to control the amount of drip you desire. The pour or spoon more of the ganache onto the top of the cake, so that it covers the entire center. Immediately lean whole Oreo cookies at an angle against each frosting swirl.
Chill the cake to set. Store at room temperature in an airtight container. Serves 12.
