I'm all about cake and ice cream. I love to make (and eat) both desserts individually, and never miss an opportunity to serve my cake à la mode. But my favorite way to combine these desserts is to, well, literally combine them, by folding big chunks of cake into freshly churned ice cream.
Don't worry, I'm not here to suggest anyone has to bake a cake as part of some sub-recipe for ice cream—that would be completely extra, even for me. Instead, I'm here to suggest saving the trimmed-off tops leftover from layer cakes us bakers tackle for birthdays, holidays, and other special occasions, and stockpiling them in the freezer. Cake trimmings are a thrifty and fun mix-in for ice cream, and they're rarely in short supply in the kitchen of an avid baker.
If you don't know what sort of cake scraps I'm talking about, you're either not wild about leveling cake layers with a serrated knife or perhaps you are wild about it, and those scraps have become your favorite snack. For those in the latter camp, you don't need to give up all your well-deserved cake munchies—the dome of a single cake is plenty for stirring into a batch of ice cream.
For those who don't bother to level their cake layers at all, let me pause for a quick PSA.
"Doming" is the term for the slight bump in the middle of the cake where it gently rises up, up, and away from the sides of the round pan. Exaggerated domes can be a sign that something's off with your formula or technique, but slight doming is quite normal. Leveling off that dome with a serrated knife ensures each subsequent layer of cake will stack up nice and neat, without buckling in the middle as the top layer cracks due to the unevenness of the dome beneath it.
Aside from the satisfaction of a job well done and the reward of a tidy-looking cake, those discarded cake tops serve a culinary function as well, providing a vehicle to test drive the buttercream, allowing for on-the-fly adjustments to the aromatics and salt. Just as you wouldn't layer ragù and béchamel into a Lasagna Bolognese without tasting them first to adjust for seasoning, no buttercream should touch a layer cake without a little doctoring.
What's more, removing the thick and heavy top crust of a cake allows its fluffy interior to better absorb moisture and flavor from the frosting. It's a win-win scenario all around, but for me, the most compelling reason to level a cake is the promise of cake scrap ice cream. Maybe not right after I make the cake, but someday.
All I have to do to make this future ice cream possible is toss my cake scraps into a freezer-safe bag, where they'll be happy to wait up to six months in cold storage. When the time comes, those frozen scraps are ready and waiting to be crumbled into a chilled dish of freshly churned ice cream.
I like to leave a few large chunks, and break-up other pieces to make something like a ribbon of crumbs, but there's no science to it—it just depends on what kind of texture you'd like to see in the finished scoops. Keep adding cake scraps and folding with a spatula until the ice cream looks right, whatever that means to you.
The only real trick is, as I mentioned, to fold the cake scraps into the ice cream by hand. If churned into the ice cream while it's still in the machine, the dasher will quickly homogenize the elements into a uniform mush—less ice cream than the sort of sugary paste you might spot on a little kid's plate after a birthday party, a mass of cake and ice cream mashed together with a plastic fork.
But when the cake morsels are folded into ice cream by hand, the two elements remain delightfully distinct, and there are near endless combinations to explore—like hazelnut ice cream with pumpkin cake tops, roasted cherry ice cream with crumbled gingerbread, or Meyer lemon ice cream with blackberry cake scraps.
In some cases, you may want to stir an extra pinch of salt into the ice cream base, to account for the sweetness the cake scraps will add. This is especially true if you want to add a ribbon to the ice cream, pushing things right on over the top.
Other times, when one element has a bitter flavor, like chocolate or espresso or a foxy caramel, that kind of adjustment may not be necessary. If you're unsure, try a spoonful of the chilled ice cream base with a piece of frozen cake to see what (if any) seasoning adjustments may be required.
So the next time you find yourself making a cake, don't let your eyes glaze over when it comes to the instructions for leveling the tops. Do things by the book (or online recipe) and your cake will be prettier and tastier than ever, while the reserved tops will provide another dessert down the road—and a chance to dream up a new ice cream all your own.