Now I would be lying if I said this recipe was easy. Or very doable. Or simple. I would not be lying if I said this recipe takes multiple days to execute without a blast chiller or liquid nitrogen. This is the kind of cake you would only make for special occasions. Between the techniques, ingredients, and equipment used to make it(Pavoni molds, silicone sphere molds, specialty food coloring powders, yuzu, and using gelatin AND agar), and just the amount of time it’ll take to set things up(you have to make and freeze solid two gelees, then make a chiffon cake, and a mousse, then freeze all of those together before glazing them), and three different tuile batters, another mousse, and a glaze to boot. Needless to say, there is a lot of things that go into this petit, singular mousse cake. Now before you let that all intimidate you or dissuade you from making this recipe, let me describe the major pros. This cake is really delicious. Like Gordon Ramsay plate lick-delicious. The blueberry and yuzu combination is sweet, tart, and tangy, and it’s addictive. This cake is really aesthetically pleasing, so whoever you are making it for will love you forever(fun fact, I made it to celebrate my own 27th birthday, and I can tell you it was the best birthday gift I ever made for myself). The chiffon cake is light and fluffy, being inspired by the mixed berry chiffon cake from Paris Baguette that will forever have a stranglehold on my heart. And the yuzu is bright, zesty, (expensive,) and citrusy, all things to make sure that this cake stays light and refreshing. This cake embodies a lot of techniques and bells and whistles, and they all come together and pay off in the end.

For the components, we have a blueberry chiffon cake, a yuzu-butterfly pea gelee insert, a blueberry gelee insert, a Yuzu Inspiration mousse, a yuzu soak, blueberry mousse, yuzu glaze, and naturally colored butterfly tuiles. With the chiffon cake, there is always a challenge with baking blueberries into anything, since your usual leavening agent(baking soda) would discolor it. So for this recipe, I went with baking powder, and relied on the egg whites to do the leavening for me. The color was a pleasant sea blue as a result of that! For the yuzu gelee insert, I used butterfly pea powder, which when mixed with acidic ingredients, goes from blue to either purple or pink. In this case, it went purple, which matched the color of the blueberry gelee! I kept them at different sizes to help differentiate them, but also since the top gelee layer, I measured it out so that it would not be completely covered by the blueberry mousse balls that were going on top of the cake(we’ll get back those in a minute). Comprising the main body of the cake is a Yuzu Inspiration(yuzu-flavored chocolate) mousse, made with fresh yuzu as well. There is also a yuzu soak for the blueberry cake, and a yuzu glaze, meant to coat the yuzu mousse and blueberry gelee. Just to balance out the number of blueberry components, and to drive in more blueberry flavor, I went with a blueberry mousse on top, set into little half spheres. On top of the spheres and around the cake, there are little blue-purple butterfly tuiles, made using the Pavoni butterfly molds, just to bring it all together and give the cake that movement and height. Overall, this is one of my favorite cakes to make(even though it took forever) and definitely to eat!

For the yuzu-butterfly pea gelee insert:
Zest and juice from 1 fresh yuzu fruit
2 tbsp yuzu juice
1/4 tsp butterfly pea powder
2 tbsp water
1 tbsp sugar
a pinch of salt
1 1/2 tsp agar agar

Bring everything to a simmer. Once dissolved, take off heat. Pour into a 5-inch ring mold that is lined with two layers of cling wrap. Freeze for 2 hours or until completely solid.

For the blueberry gelee insert:
1/4 cup blueberry puree
2 tbsp water
1 tsp yuzu juice
a pinch of salt
1 tsp granulated sugar
1 1/2 tsp agar

Bring everything to a simmer. Once dissolved, cool down the mixture and pour into a 4-inch ring mold that is lined with two layers of cling wrap. Freeze for 2 hours or until completely solid.

For the blueberry chiffon:
3 egg whites
1/3 cup granulated sugar
2 egg yolks
2 tbsp canola oil
3 tbsp blueberry puree
1/2 tsp baking powder
a pinch of salt
1/2 tsp vanilla extract
1/2 cup all-purpose flour

Whip egg whites with sugar to stiff peaks. Whisk egg yolks with canola oil, blueberry puree, baking powder, salt, and vanilla. Sift into the blueberry mixture your flour, then fold into that the egg whites. Spread on a lined quarter sheet tray. Bake at 350 degrees F for 15 minutes.

For the yuzu soak:
2 tbsp yuzu juice
a pinch of salt
1/4 cup water
1 tsp honey or sugar

Mix until combined.

For the Yuzu Inspiration mousse:
3oz Yuzu Inspiration
zest and juice from 1 yuzu fruit
1 tsp gelatin powder + 2 tbsp yuzu juice
a pinch of salt
1/4 cup water
3 egg yolks
2 tbsp granulated sugar
1 cup heavy cream, whipped stiff

Heat up Yuzu inspiration, yuzu juice, gelatin, salt, and water until the Yuzu Inspiration and gelatin are fully dissolved. Whisk half of the liquid into the egg yolks and sugar then whisk the egg yolks into the yuzu mixture, stirring on low heat for 2-3 minutes. Strain out any lumps and cool down the mixture. Then fold into that the heavy cream.

For initial assembly:
Cut 2 6-inch disks out of the chiffon cake. Line the bottom of a 6-inch ring mold with 2 layers of cling film and line the sides with acetate. Place down the blueberry gelee disk at the bottom first, in the direct center of the mold. Pour in 1/3 of your mousse. Brush the cake disks with soak and place one of the rounds down. Then pour in another 1/3 of your mousse. Then place in the yuzu-butterfly pea gelee disk. Then pour in the last of your mousse and press in the last cake round. Freeze solid, another 3-4 hours.

For the blueberry mousse balls:
3 tbsp blueberry puree
1/4 tsp gelatin powder + 1 tbsp yuzu juice
2 tbsp water
a pinch of salt
1 tsp granulated sugar
1/4 cup heavy cream, whipped stiff

Heat blueberry puree with gelatin, sugar, water, and salt. Once everything is dissolved into the puree, take off heat and cool down. Fold in the heavy cream. Pour into 1-inch sphere molds and spread. Freeze solid, about 1-2 hours.

For the yuzu clear glaze:
1/4 cup yuzu juice
2 tbsp granulated sugar
1/4 cup water
1 tsp gelatin powder + 1 tbsp water
a pinch of salt

Heat everything until dissolved. Keep at 90 degrees F for glazing with.

For the butterfly tuiles:
1 egg white
1/4 cup all-purpose flour
2 tbsp canola oil
1/3 cup confectioner’s sugar
a pinch of salt
1/4 tsp butterfly pea powder
1/4 tsp purple yam powder

Mix everything besides the butterfly pea and purple yam powders. Divide the batter into two, and mix in the powders, one into each batch. Then take about 1/3 of each batter and mix them together to form a darker purple tuile batter. Either pipe the batters onto a lined sheet tray, or spread them onto Pavoni butterfly molds. If using the molds, bake at 350 degrees F for 8 minutes. To get the butterflies to have propped up wings, I used the back of the 1-inch sphere mold. If free-handing the tuiles, bake them until they are no longer flimsy(you should be able to lift them off the mat in one piece), then press into a curved surface to create the effect of the butterfly perching.

For final assembly:
On an elevated surface, pour the glaze over the still-frozen but unmolded mousse cake. Freeze for an hour, and then place on top your blueberry mousse spheres. Garnish with the butterfly tuiles to finish off the cake.