Every year around mid-June my inbox is flooded with press releases for flag cake recipes, all of which boast new and exciting takes on the patriotic dessert. Usually I ignore them, because flag cakes have been done to death, but America has really outdone herself this year, and she deserves a cake—an unprecedented cake, a flag cake flambé.
Why flambé an American flag cake?
Flambé is a classic French method that involves soaking a food with high-proof alcohol and setting it on fire. The ethanol burns brightly, leaving behind a caramelized dessert and rich boozy syrup. (It is a fallacy that all “of the alcohol burns off,” as it takes an ABV of at least 40% to catch fire; once it drops under that, the flame will die out, but the remaining liquor could still have an ABV somewhere in the 40s.)
Most flag cakes are cloying and one-note, all show and no substance, but the char from the fire and bite of the rum tempers all that sugary sweetness and adds depth, turning a cutesy tone-deaf dessert into something with flavor, character, and pizzaz (and lightly roasted strawberries). Plus it looks impressive!
What kind of booze should I use?
A lot of flambé recipes call for a “normal” rum with an ABV of 45% or so. That works if you’re going to be heating the rum before hitting it with a flame, but we’re working with cake, and hot rum will melt the buttercream and sink far into the cake before you have a chance to light it ablaze. An overproof rum—like 151—is what you want, as it lights almost instantly, even on a chilled cake (which we will get to in a moment).
It’s true that 151 is a little “more dangerous” to work with, but on a scale from one-to-illegal abortion, it’s like a three. As long as you pour the rum on the cake before you introduce the flame, you should be fine. (And if you want to add more rum, so that your flames may burn even brighter and bigger, just do so from a smaller secondary container, otherwise you risk the flames traveling up the stream of booze and to the bottle, which could explode in your hand.)
How to make a flag cake
To make a flag cake, you’ll need a plain white sheet cake, with a border of buttercream (to keep the rum on the cake). You can either make your own cake from scratch, or buy a pre-made sheet cake from the grocery store (which is what I did).
If you make the cake from scratch, you can borrow from the king cake and bake a little plastic baby inside one of the layers for a fun twist. Whoever finds the baby in their piece of cake has to keep it forever, even if they do not want it, even if they did not want any cake to begin with, even if the cake was forced on them against their wishes. (Hit the baby with the knife while carving the cake, however, and you go straight to jail.)
Once you have a layer cake, all you have to do is get some blueberries and strawberries and arrange them on top of the cake so it vaguely resembles an American flag. (I say “vaguely” because you will not be able to fit 13 strawberry stripes onto your cake.) Leave the blueberries whole and cluster them into a square in the upper left corner. Slice the strawberries, then cut those slices in half before laying them down in as many horizontal lines as you can fit on the cake.
How to flambé a flag cake
Once your flag cake is decorated, go ahead and pop it in the freezer for a bit to chill, to prevent the frosting from melting the moment you flambé. Half an hour to an hour should suffice. Grab a bottle of overproof rum (such as 151) and pour some into a squeeze bottle or other, similar vessel, so you can aim the booze in between the strawberries—into the “rum gutters,” if you will. You’ll also need a candle or utility lighter, something long to keep your hand away from the flames. Add the rum to the rum gutters, then light the rum on fire.
The rum will burn brightly, gently roasting the berries while melting the sugar in the buttercream to make a sticky, almost brûléed, candied crust. The rum will also soak into the top layer of the cake, creating a decidedly adult dessert with lots of deep, caramelized, rummy flavor.
Serve and enjoy your cake immediately, while you still can. (Who knows! If SCOTUS keeps tearing along down their current path, this cake may one day be illegal.)