First, find a good reason to make one. I knew for months that I wanted to make an ice cream cake for Evan's birthday party. He tried to steer me away, saying it would be too messy, too hard to serve, etc. Indeed, I usually avoid making cakes for parties, preferring to bake simpler handheld apportioned desserts like cupcakes. But I felt a special occasion such as a double 30th birthday party (he shared his party with his best friend who was born only 10 days away) merited an extra special baking adventure, especially for someone who loves ice cream as much as Evan.
Second, decide on your preferred style of ice cream cake. It turns out it's hard to find basic instructions for ice cream cake. There are lots of variations out there, often involving elaborate cookie studded ice cream or unusual flavors. Some aren't real cake, just cookies crumbled into a layer topped with ice cream. I scoff at those. Some are made of ice cream spread between two whole layers of cake. But Evan doesn't like regular cake that much, so I didn't want to make the cake primary and the ice cream secondary. Some versions involve a layer of ice cream molded in a cake pan to perfectly match a layer of cake in size. However, those recipes call for a lot of ice cream (two quarts), which would consume too much money and time to make. Many suggest whipped cream as frosting. But I don't like whipped cream.
Decide on a cake of your own design: In my case, it was a Vanilla Ice Cream Cake with Blueberry Filling: half a layer of vanilla cake, topped with blueberry filling, then a layer of vanilla ice cream, then half a layer of vanilla cake, and then frosted with vanilla ice cream. After it's all spent time in the freezer together, the slightly-ice-cream-soaked-half-cake-layers are just the right size to provide a chilled sturdiness, while the pure vanilla ice cream shines and the blueberries jazz it up.
Two or three days ahead, bake the cake. I used Smitten Kitchen's Best Birthday Yellow Layer Cake. Like Evan, I think regular cake is kind of boring, but Deb did not let me down and this cake was surprisingly tasty, so I kept sneaking bites of the bits that stuck to the pan. I have just one cake pan that is a rectangle around 7x11 inches, so I diminished her recipe by a quarter and left out the buttermilk and salt because no one misses that. Cream 1 1/2 sticks of butter and 1 1/2 cups sugar, whisk in 3 eggs, 1 cup milk and 2 tsp vanilla. Dump in 3 cups flour, 1 1/2 tsp baking powder and 1 1/4 tsp baking soda and beat to combine until smooth. Bake at 350 for 35-40 minutes. I had trouble getting the cake out of the pan even after it had cooled for an hour, so I employed a trick of placing a wet washcloth around the bottom of the pan for a few minutes before trying again, and it actually worked. Wrap the cake in plastic wrap and store it in the freezer.
Sometime between making the cake and the ice cream, make the blueberry filling. It is essentially a blueberry jam, and you want to make sure you leave enough time for it to chill before assembling the cake. In a saucepan, combine 1 pint of blueberries, 1/2 cup sugar, 1/2 cup water, 2 tbsp cornstarch and the juice of half a lemon. Let the mixture simmer on low for about a half hour, until the juice has evaporated off and it's thick enough to spread. Let it cool completely.
One day ahead, make the ice cream and assemble the cake. Homemade ice cream is soft enough to spread easily after it first comes out of the ice cream machine, so you want to have everything ready to assemble as soon as it is done churning. I followed the trusty recipe for basic vanilla ice cream that is found in the little pamphlet that accompanied my ice cream machine. Whisk 3/4 cup sugar and one cup milk until the sugar is mostly dissolved. Whisk in 2 cups cream and 2 tsp vanilla. Turn on your ice cream machine, pour it in, and let it churn for 15 minutes.
While it churns, begin to assemble the cake. Remove the cake from the freezer and carefully carefully slice it in half. You probably want to use a long serrated knife. Spread the blueberry preserves over the bottom layer and stick it back in the freezer to let the blueberry layer firm up a bit.
When the ice cream is done churning, spread about half of it on top of the blueberry filling. Lay the second layer of cake on top and then spread the remaining half of the ice cream across the top. Leave the sides for last and do it quickly. As I learned, ice cream does not work that well as "frosting" since it melts and drips rather than adhering to the sides. Nevertheless, do your best and ignore the mess. You can cleanly scrape away the melted puddle around the cake after it has spent its time in the freezer.
Store the ice cream cake in the freezer until just before serving. Luckily, it fit quite well inside of my cupcake carrier, which fit just barely into my freezer. Otherwise I probably would have tried to wrangle plastic wrap around it.
When it comes to time to serve, make sure all accompanying items are at hand, since time is of the essence when it comes to serving ice cream cake. We ushered everyone outside to wait with champagne and sparklers, while I scrambled last minute to find a lighter for the candles. Then I was glad to have a real candlelit cake to present for the happy birthday chorus moment. This was followed by shouting "quick come and eat the cake before it melts!" while the other birthday boy was presented with his present, a bow-adorned bicycle. We got about 20 small squares out of this ice cream cake, which turned out to be enough, because as anyone who's been to a wedding knows, not everyone wants cake at a party.