Layers of tender sponge cake and pumpkin mousse, topped with a crispy nest of honey coated crispy sweet potato. An easy fall dessert that looks beautiful.
Someone once told me that "you can tell a baker and a chef apart by whether they measure things or not". I fit squarely into the second category, and until I started developing recipes for other people, my measuring cups sat idle in the back of my cupboard. It's not that I have anything against precision. I just don't like feeling constrained by rules.
Sadly, when it comes to baking you can't go adding more leavening after the cake fails to rise, so you have one shot to get it right. That's why I don't bake much, and I'm perfectly pleased with leaving pastry in the hands of a practiced pâtissier. Besides, the whole "science of baking" thing runs contrary to my no recipe credo and I have a brand to uphold... right?
My first inclination was to do a pumpkin pie, since there is no need for the filling to miraculously rise, and pie crust is something that I can actually bake without evoking the Holy Spirit. The problem is, I really dislike pumpkin pie. I've tried everything from turning it into a cheesecake, to making it a custard and brûléeing the top, but it's just not something I'm very fond of. Call me ethical, but publishing a dish I don't love seemed wrong.
Part of my problem with pumpkin pie is with the pumpkin. After years of denial, I'm finally coming to terms with the fact that I just don't like run-of-the-mill varieties of pumpkin very much. Kabocha (which literally means "pumpkin" in Japanese), on the the other hand, is a breed of pumpkin I can get behind. With jade green skin and firm orange flesh, Kabocha is like a love-child of a butternut squash and sweet potato. In Japan, it's mainly used in savory dishes, but the sweet starchy flesh is perfectly suited to make an appearance in a dessert.
This cake is the embodiment of fall, using seasonal ingredients like kabocha and satsuma imo, which carry the nutty flavors of the season, juxtaposed by the crispy texture of "fallen leaves" in each bite. I know it sounds rather complicated, but it's not as hard as you'd think. Check out the video below if you don't believe me:-)
- Setup a double boiler with a pot large enough to hold your mixing bowl then bring the water to a simmer. Move your oven rack to the middle position and preheat to 400 degrees F. Prep an 18″ x 13″ jelly roll pan by lining it with parchment paper, then buttering the parchment paper.
- Put the eggs, yolks, sugar and salt in a metal mixing bowl and whisk to combine. Put the bowl on your double boiler and whisk, heating until the mixture reaches 100 degrees F (luke warm). Mount the bowl on a mixer and beat on high with the whisk attachment for 5 minutes. The volume will triple and pale yellow ribbons of egg will flow off the whisk when they’re ready.
- Sift together the flour and cornstarch. When the egg mixture is ready, add 1/3 of the flour mixture into the eggs and gently fold together the flour and eggs. Repeat twice more, folding between each addition until you don’t see any more clumps of flour. Pour the batter into the prepared baking sheet, and smooth off the top (a pastry knife or a clean plastic ruler works great for this). Bake for 7-8 minutes or until a toothpick comes out clean. Let the genoise cool on a rack. (adapted from Tartelette)
Sweet Potato Honey Cake Recipe
- To make the mousse, put the kabocha, water, sugar and honey in a pot and simmer for 15-20 minutes or until the pumpkin is fork tender. When it's done, turn off the heat and use a slotted spoon to transfer the pumpkin to a bowl and let it cool.
- Add 2 tablespoons of water to a small bowl and sprinkle the gelatin on top. When the kabocha has cooled, pass it through a potato ricer twice so there are no lumps (you could also use a food processor. Measure out 1 packed cup of kabocha puree into a bowl.
- Whip the cream in the bowl of an electric mixer and add the honey when the cream holds soft peaks. Continue beating until the cream holds stiff peaks. Heat the gelatin in the microwave for 10-15 seconds until the gelatin is melted, then pour the gelatin into the pumpkin mixture along with a few spoonfuls of whipped cream and and quickly stir it all together. The gelatin will help the whipped cream hold its loft after you mix it with the pumpkin. Dump the rest of the whipped cream into the kabocha mixture and gently fold it together.
- Cut 12 rounds from the cooled genoise using a 2 1/2" cookie cutter or ring mold (a small can opened on both ends works in a pinch). Dip the mold in the liquid you used to cook the pumpkin to prevent the cake from sticking to the mold.
- Cut six 4" squares of parchment paper. Put the ring mold on a piece of parchment paper and drop a round of genoise to the bottom of the mold. cover with with a few heaping tablespoons of mousse, then smooth the top. Drop another round of genoise on top then top with another layer of mousse. Gently pull the ring mold off the cake and repeat with the other 5 cakes. Chill the cake in the refrigerator for at least one hour to set the mousse.
- While you're waiting for the mousse to set, heat a pot filled with 1" of vegetable oil until it reaches 350 degrees F. Shred the sweet potato into a bowl of water and rinse several times to remove the excess starch. Drain the potato and put it in a salad spinner to remove as much moisture as you can (paper towels work too)
- When the oil is up to temperature, carefully put a handful of shredded potato into the oil and fry until brown and crunchy. Remove with a wire mesh frying strainer and dab on a paper towel before putting into a metal bowl. Quickly drizzle with honey and toss to coat each strand of sweet potato with honey. Repeat with the rest of the potatoes, then sprinkle with the black seasme seeds.
- To serve, plate each cake and top with a nest of fried honey potatoes.