Preheat oven to 200 degree celsius or 400 fahrenheit.
Slice stale bread into small squares.
Transfer onto a baking tray lined with parchment paper.
Wack into the oven and toast until browned.
Remove from oven and transfer into a food processor.
Blitz until bread crumbs form and set aside.
Turn the oven down to 175 degree celsius or 350 fahrenheit.
Grease the cake pan with butter.
Lay parchment paper overhanging from the cake pan if using a square cake pan.
If using a round cake pan, lay a piece of parchment at the bottom.
Brush the paper with butter as well.
Add bread crumbs into the cake pan.
Swirl to coat every nooks and cranny with bread crumbs.
Tap out any excess.
Set aside until ready to use.
Melt butter in a skillet over medium heat.
Once the butter has melted, remove from heat and add chocolate.
Mix to combine well and until the chocolate has melted.
Sieve in the matcha powder.
Stir to combine well, making sure no lumps.
In a large mixing bowl, add eggs and sugar.
Using a hand mixer, whip until tripled in volume.
Fold in the chocolate mixture in portions.
Once the chocolate mixture has fully incorporated, fold in the flour in 1/3 portions.
Once the flour has fully incorporated, add in salt, yuzu zest and yuzu sake.
Give it a final fold and transfer it into the prepared cake pan.
Wack into the oven and bake for 20 to 25 mins. Do not bake longer than 25 mins.
The center should be still soft and molten.
Set aside to cool down completely.
As it cools, the sides will pull away from the cake pan.
Dust some icing sugar and matcha powder over the top.
Unmold, slice and serve at room temperature or chilled.
I prefer mine at room temperature.
