Remove the cake layers from the freezer about 30 minutes before you want to assemble the cake. I take them out to thaw while I am preparing my buttercream and ganache. You want the layers to be cold, but not completely frozen to decorate.
Once your cake has thawed enough to safely handle, level the layers by slicing a thin layer of cake from the top with a serrated knife. These cakes bake pretty flat, but you still want to take a little off the top to use for the 'ice cream' cake ball. Mix your cake scraps with a spoonful of buttercream to form a dough-like mixture. Shape into a ball and place in the freezer while you prepare the rest of the cake.
To assemble the cake, place a dab of buttercream on your cake board or plate and then place the first layer of cake on top. Spread a layer of buttercream on top. Stack the next cake layer on top and repeat, ending with the final layer of cake, top side down.
Using an offset spatula add a thin layer of buttercream on the sides and top of the cake, scraping off any extra with a bench scraper or icing scraper. This is your crumb coat. It’s ok if it looks messy, the goal is to trap the crumbs in this layer so that the final layer of buttercream is crumb-free and smooth. Refrigerate the crumb-coated cake about 15 minutes or until firm to the touch.
Now frost the cake with a thicker layer of buttercream. Smooth with a bench scraper or offset spatula. Chill the cake for 15 minutes to set the buttercream before adding your ganache drip. *See Notes below about using an acrylic disk or cake board to frost your outer layer*
I like to do a test drip, either on the back of the cake or the side of my cake scraper or even just a plate held vertically. You can add more cream if you want thinner drips or allow the ganache to rest a bit to thicken up if you want thicker drips.
Using a spoon, guide your drips around the sides of the cake and then pour some additional ganache on top of the cake and smooth out with an angled spatula or the backside of a spoon.
Take your cake ball out of the freezer and drop it into your bowl of ganache, and rotate to completely cover. Using two forks place your ganache-covered cake ball on the center of your cake.
Place your wooden skewer down through the center of your cake ball and into the cake. You want about 2 inches to be showing, if the skewer is too long you can trim it.
Dip the top of your ice cream cone in ganache and then place overtop the skewer to stick to the cake ball.
Decorate with sprinkles and additional mini chocolate chips.