Line a 9 inch round pan with parchment paper or plastic wrap. Spread ice cream evenly into pan. Freeze for 8 hours or overnight.
Cake
Preheat oven to 350°F. Line two 9 inch round cake pans with parchment paper, then butter and flour them.
Sift together the flour, sugar, cocoa powder, baking powder, baking soda and salt in a medium bowl and set aside.
In a large mixing bowl, beat together the buttermilk, vegetable oil, greek yogurt, eggs and vanilla extract until smooth. Slowly add the dry ingredients to the wet ingredients with the mixer on low until there are no clumps of flour. Add the hot coffee and mix until just combined. Batter should be thin and smooth.
Pour the batter in the cake pans and bake for 20-25 minutes or until a toothpick inserted in the center comes out clean. Remove and let cool for 5 minutes in pan. Run knife round edges of the pan and invert on cooling racks. Let cool completely before using.
Frosting
In a large mixing bowl with a whisk attachment, whip the cream, powdered sugar and vanilla extract on medium-high speed until soft peaks form, about 3-4 minutes.
To Assemble
To assemble, place one cake layer on a serving plate. Invert the ice cream onto the cake layer, removing the plastic wrap. Top with remaining cake layer. Spread whipped cream frosting over the top and sides of the cake. Top with some cookie dough if desired. Freeze for at least 2 hours or until firm. You can freeze for up to 1 month.
Notes
Line round cake pans with parchment paper or plastic wrap so you can easily pull the ice cream out of the pan when it is completely frozen.
Use same pans you froze the ice cream in to make cake so you have the same size cake.
Use quality unsweetened cocoa powder for cake. No need to use Dutch processed.
Make sure buttermilk and eggs are room temperature which creates a fluffy rather than dense cake.
Don't skip out on the coffee which enriches the chocolate flavor.
You know cake is done when you insert a toothpick in the center and it comes out clean.
Let cakes cool completely before assembling layers, otherwise your ice cream will melt.
After frosting cake, let sit in freezer for 2 hours before serving.