The idea behind this cake came from a very unusual silicon mold I purchased from Amazon. I knew that just from the triangular prism shape of the final cake, that each slice would be a little tear drop-triangle-chestnut-looking thing. I thought it would be cute if I made some mousse cakes that were visual plays on onigiri, the triangular Japanese rice ball. The colors of onigiri are generally the white rice, a black strip of nori, or dried seaweed, and typically some sort of filling, but for this variation, I opted to not include one.

For my Citron Othello, I wanted to do a black and white cake, but accented with lemon. So my final product was a black sesame-charcoal genoise with lemon-white chocolate mousse and lemon-dark chocolate mirror glaze. I included the lemon in both the mousse and the glaze because white chocolate is so cloyingly sweet that even though my mousse technically has no sugar in it, I want that lemon to obliterate any notion of my dessert being too cloyingly sweet.

For the genoise:
1/2 cup all purpose flour
1/2 teaspoon baking powder
1 teaspoon activated charcoal
2 tablespoons black sesame powder
2 tablespoons canola oil
1/3 cup granulated sugar
2 eggs

Whip the sugar and eggs into ribbon stage. Sift the flour, baking powder, and black sesame together. Bloom the charcoal into the oil. Fold together the ingredients. Pour into a rectangular baking mold (I used a slightly different one that what was pictured, but it’s the same general concept) and bake at 350 degrees F for 15 minutes. Allow the cakes to cool and remove. Cut off any excess tops. You need just 6 perfect rectangles for the cake.

Sesame soaking liquid:
1/4 cup water
2 tablespoons black sesame powder

Puree ingredients together and strain. Soak the cakes in this liquid before pressing into the mousse.

For the mousse:
1 cup white chocolate
juice from 1 lemon
zest from 1 lemon
1 3/4 teaspoons gelatin powder + 1 tablespoon lemon juice
1 cup heavy cream, whipped to stiff peaks
a pinch of salt

Bloom gelatin in lemon juice. Reduce into the remaining lemon juice and zest. Combine with melted white chocolate and continue to mix until the mixture is a fluid liquid. Once the white chocolate, while still liquid, is room temperature, fold in the whipped cream. Pour into the mold. Press the cakes into the center of the mousse in the mold, doing three columns of two, and freeze overnight.

For the glaze:
juice from 1 lemon
zest from 1 lemon
2 teaspoons gelatin powder + 1 tablespoon lemon juice
1 cup dark chocolate chips
1/4 cup warm water

Bloom gelatin in lemon juice. Reduce the lemon juice, zest, and gelatin. Add in the dark chocolate and puree until smooth, adding in the warm water as needed to smooth and thin out the mixture. Allow the glaze to cool to just above room temperature, but make sure it stays liquid.

Assembly:
Over a cooling rack, pour the glaze onto the frozen mousse cake. Remove any excess glaze off of the edges, and refrigerate until the glaze is set. Cut using a warmed knife.