This fudge crunch ice cream cake is inspired by the dairy queen ice cream cakes I loved getting for my birthday growing up, and upleveled with the swap of chocolate cake instead of chocolate ice cream.
Whisk the cocoa powder with warm water and set aside.
Add the all purpose flour, sugar, baking soda, and salt in a mixing bowl and mix on stir until combined (for about 20 seconds).
Add the milk and lemon juice in another small or medium sized mixing bowl. Let sit for 5 minutes, then add the oil, egg, and vanilla extract. Whisk until combined.
Add wet ingredients to the dry ingredients, and whisk for 1 minute on low. Increase speed to medium, and beat for another 1 minute.
Add the chocolate water to the mixture, and beat for 30 seconds, or until just combined. Avoid overworking the batter. Remove the mixing bowl from the stand mixer, and use a spatula to make sure all the batter is integrated (the very bottom may not be as chocolatey).
Spray a 9 inch round cake pan with non-stick spray. Line the cake pan with a piece of parchment paper. Transfer batter to the pan, and bake for 35 minutes, or until a knife comes out of the center cleanly.
Cool completely, then flip out the cake.
For the Fudge crunch
Preheat oven to 350 degrees.
Food process the oreos for 20 seconds. Combine the oreo crumbles and melted butter and stir until well combined. Spread the crumbs evenly onto a baking sheet.
Bake for 8-10 minutes, then allow to cool. When the crumbs are hot, they will be soft so make sure to cool completely. Set aside.
Make the fudge - add the chocolate chips and corn syrup to a medium sized bowl. Heat the ½ cup of heavy whipping cream just until it begins to simmer, then pour it over the chocolate chip mixture. Allow to sit for 2-3 minutes, then whisk until smooth.
To Assemble the ice cream cake
Remove the vanilla ice cream from the freezer and let sit for 15 minutes.
Line a 9 inch cake pan with 2 pieces of plastic wrap. Make sure all the sides are covered and the plastic hangs over the edges of the cake pan.
Transfer the vanilla ice cream to the plastic lined cake pan. Smoothen it (or use gloves to press the ice cream into the shape of the cake pan.
Add the cookie crumbles to the vanilla ice cream layer, then pour the fudge over the cookie crumbles.
Add the chocolate cake layer on the fudge and gently press down.
Freeze for about 2 hours, until mostly firm.
Use the clear wrap to lift the frozen cake out of the pan, then place it on parchment (or cardboard) lined plate / cake stand.
Make the whipped cream - add the heavy whipping cream and sugar to a large mixer bowl. Whip on high speed until stiff peaks form, about 5 minutes on high.
Frost the cake with the whipped cream and decorate as desired. I used colorful sprinkles from whole foods and gel icing from safeway (whole foods isn’t going to have gel icing FYI!).
Keep the cake frozen until ready to serve. The cake will last in the freezer (after being cut into) for up to 1 month if stored in an airtight container.