Oreo Ice Cream Cake

The Art.
    Last summer I attempted to make my very first ice cream cake, which resulted in a literal and metaphorical meltdown that I never want to experience again. As I was standing in the middle of my kitchen frantically scooping up icing that was sliding down the sides of the melting cake, I told myself that there must be a better way. And I'm proud to say that I have found it: I present to you the new and improved Oreo Ice Cream Cake! By baking the chocolate cake layer in a springform pan, then layering the ice cream on top, the cake is manageable and easy to cut. The cake is then covered with a stabilized whipped icing that is simultaneously tasty and insulates the ice cream, and Oreo cookies act as crunchy garnish.

The Science.
    The main problem with the first ice cream cake attempt was that I bought cheap ice cream. Ideally, ice cream should have 10% milk fat in the liquid solution, and once it is frozen it should be 50% air, 30% ice, 15% sugar solution, and 5% fat [1]. Both the milk fat and the air act to insulate the ice cream temperature [2]. The store brand ice cream that I purchased was made with skim milk, stabilizers, and additives that gave the final product a creamy texture and mouthfeel, without having any cream in it. However, without milk fat, this ice cream had a very low melting temperature and would start melting quickly. When making an ice cream cake, you want to use an ice cream that has a high melting temperature, so that it will stay solid longer while you're working with it. For this cake, I perused the frozen dairy isle at the grocery store for the ice cream brand that had the most cream. I was shocked to find that several name brands were actually not ice cream, but "frozen dairy dessert." Most others were made with skim milk, like the one I had previously bought. I finally settled on Blue Bunny, because it had whole milk and cream as the first two ingredients. It was definitely worth taking the time to read the labels, because making and decorating this cake went so much smoother with the high fat ice cream.

The Recipe.

Ice Cream Cake:
1 cup sugar
1 cup flour
3/4 teaspoon baking powder
3/4 teaspoon baking soda
1/2 teaspoon salt
1/2 cup boiling water
1/3 cup cocoa
1 egg
1/2 cup milk
1/4 cup vegetable oil
1 teaspoon vanilla extract
1/2 gallon Blue Bunny Cookies & Cream ice cream
10 Oreo cookies, crushed

    Preheat oven to 350^oF and adjust rack to center position. Coat a 10"x 3" springform pan with baking spray. Combine sugar, flour, baking powder, baking soda, and salt in a medium bowl. In a small bowl, dissolve cocoa in boiling water to allow it to "bloom." In a large bowl, beat together egg, milk, oil, and vanilla. Add dry ingredients and beat on medium speed for 2 minutes. Stir in bloomed cocoa. Pour batter into prepared pan, and bake 30 minutes. Cake may be a little soft in the center--this is what makes it easy to cut when frozen. If the cake is crowned, press it flat with a damp paper towel as I showed here. Cool in pan for 2 hours, until room temperature.
    When the cake is cool, thaw the ice cream at room temperature for 15-20 minutes. You want it to be soft enough to spread on top of the cake, but not completely melted. Spread the entire tub of ice cream over the cake, and smooth out with a spatula. Place the cake in the freezer for at least 4 hours, or overnight.

Stabilized Whipped Icing:
2 cups 40% heavy whipping cream
1 teaspoon cornstarch
1/2 cup powdered sugar

    Pre-chill a large metal mixing bowl and your mixer's beating blades in the freezer for 10 minutes. Meanwhile, make an ice bath in a pie plate. Place the bowl on top of the ice bath, and beat the cream in the bowl on medium speed until soft peaks form. Beat in the cornstarch and powdered sugar, and continue to beat until stiff peaks form. Be careful not to whip the cream too fast or too long, or your icing will curdle. The cornstarch acts as a stabilizer and will absorb the water in the cream, so the icing will stay whipped in the refrigerator for several days.

Assembly:
     Take the frozen cake out of the freezer. Run a knife along the edges of the pan to loosen the ice cream, then remove the sides. If your cake layer pulled away from the sides of the pan after it baked, you will have some ice cream that dripped all the way down to the bottom. This is ok, you will still see the layers when you cut the cake.

    With a spatula, spread an even layer of whipped icing all over the top and sides of the cake. Spread the crushed cookies on top. If desired, pipe a border of whipped icing and place a cookie in the center for garnish. Place the cake back in the freezer for at least 30 minutes to set. Let cake sit at room temperature for 15 minutes before serving.

1. Gillies, D and Greenley, K. "ESR/Spin Probe Study of Ice Cream." Journal of Agri. and Food Chem, 2006. Vol. 54 (14), pp 4943–4947.
2. Galvin, Lori et al. Test Kitchen Favorites. Brookline, MA: America's Test Kitchen, 2006.