White Chocolate Cream Filling

1. Put the white chocolate in a small bowl and set aside.
2. In a small sauce pan, bring heavy cream to a simmer.
3. Pour the warm heavy cream over white chocolate, stir the chocolate until melted. Keep stirring until smooth. Cover the bowl and chill in the refrigerator for at least 2 hours (Cream needs to be cold before using).
4. Once the cream is chilled and the sponge cake is ready to be assembled, take the chilled cream from the fridge and beat until soft peak forms.

Matcha Sponge Cake

1. Preheat the oven to 375°F. Line a 9×13 baking pan with parchment paper. Leave extra parchment paper hanging on the side so it’ll be easier to lift up the cake later.
2. Separate the eggs. Put 4 egg yolks in one bowl, and 4 egg whites in another bowl.
3. Whisk the egg yolks. Then add ¼ cup of sugar and continue whisking until thickened and pale. Sift cake flour and matcha powder and add 3 tbsp of milk into the egg yolk mixture. Mix until combined.
4. Using a handheld or standing mixer, beat the egg whites until foamy. Gradually add ¼ cup of sugar and continue beating until soft peak forms (when you lift up the whisk attachment, it should hold with the peak drooping over looking like a hook).
5. Take ⅓ of the egg whites and fold it into the egg yolk mixture. Repeat this twice with the remaining egg whites, folding until evenly incorporated. Stop when no white streaks remain, do no over mix.
6. Pour the batter onto the prepared baking sheet. Tap the baking pan a few times onto the counter or use a spatula to smooth the surface.
7. Bake for 11-12 minutes at 375°F.
8. Take the sponge cake out of the oven. While it is still hot, take another sheet of parchment paper and place it on top of the cake (now the cake is sandwiched between two sheets of parchment paper). With one hand or use another baking pan supporting the top, flip the cake over.
9. With the bottom now on top, gently remove the parchment paper. Take a third clean sheet of parchment paper, place it on top of the cake, then flip the cake over again. Remove the top parchment paper.
10. While the cake is still warm, take one end of the parchment paper and gently roll the cake away from you. Once the cake is rolled up, put it aside and let it cool. This step helps shape and stabilize the cake roll (rolling while the cake is still warm helps prevent cracks).

Assemble

1. Once completely cooled, unroll the cake. Using a spatula, spread the white chocolate cream filling over the sponge cake, leaving around ½ inch boarder on all sides.
2. Carefully roll the cake into a tight spiral shape (without parchment paper this time). Wrap tightly in plastic wrap and refrigerate for at least 2 hours before slicing.
3. Before serving, slice off the ends to show the beautiful cream swirls! To serve, use a serrated knife and cut the roll into 6-7 slices. Dust with powdered sugar or matcha powder, if desired.