With stripes of vanilla and chocolate in two layers, this Zebra Cake is finished with a rich cookies and cream frosting. It's so completely delicious and fun, and despite its impressive appearance, it's actually very easy to make!
Preheat the oven to 350°F. Spray two 9-inch round cake pans with cooking spray. Add a circle of parchment paper to the bottom of each pan, and spray the top with more cooking spray, set aside.
In a large bowl with an electric hand mixer, stir the cake mix, milk, oil, and egg whites for 30 seconds until it comes together. Mix on medium speed for 2 minutes.
Take half of the cake batter and pour it into a medium-sized bowl.
To the remaining cake batter, add the cocoa powder and stir until just combined.
Working with both cake pans, add about ¼ cup of the white cake batter to the center of each pan. Add about ¼ cup of the chocolate batter into the center of the white batter in each pan. Continue alternating the batters until they are used up, and each pan has the same amount. (If you find the batter isn’t spreading, you can tilt the baking pan until it fills out the bottom; this will not mess up the zebra design.)
Bake for 22-25 minutes or until a toothpick inserted into the center comes out clean. Let the cakes cool completely in the pans.
Make the Frosting
Place the Oreos into a food processor and process into crumbs; set aside.
Place the softened butter and cream cheese into the bowl of a stand mixer with the paddle attachment, and cream together until smooth.
Add the powdered sugar a little at a time until fully combined, and scrape down the sides as needed.
Add the heavy cream and vanilla, and stir until just combined. Place the mixer on medium-high speed and whip for 3 minutes until light and fluffy.
Add the cookie crumbs and stir them in until combined. (I like to then use a spatula to mix it a little more by hand to make sure the cookie crumbs are evenly distributed.)
Frost the Cakes
Cut any doming off the cakes so the tops are flat. Put one of the cakes bottom side down onto your serving platter. Add about 1 cup of the frosting and smooth it out to the edge.
Place the second cake on top, bottom side down, onto the frosting. Add a thin layer of frosting over the whole cake. Place in the fridge for 1-2 hours to set up.
Once chilled, add another layer of frosting onto the whole cake. Take the remaining frosting and decorate as you wish, and add mini Oreos if desired. Cut and serve immediately.