Preheat the oven to 220 °C or 425 °F.
Line the cake pan with two layers of parchment paper. Make sure the parchment comes at least 2? above the top of the pan on all sides. It is okay to pleat the parchment because the cake should come out with a non-perfect clean, smooth edge.
In a small bowl, sift the matcha powder. Add hot water. Mix until combined. Set aside.
In a large bowl, whisk the softened cream cheese until creamy.
Add icing sugar. Continue to whisk until all sugar is dissolved and combined into the cream cheese.
Add 1 egg at a time. Turn on low speed to whisk until combined, before adding another one. Don't forget to add the extra egg yolk as well. The texture of the cream cheese mixture should be creamy and light.
Add matcha mixture (from step 1) into the batter. Use a spatula to mix until combined.
Add whipping cream. Use a spatula to mix until combined.
Sift in corn starch. Use a spatula to mix until combined.
Pour the cake batter into the lined cake pan. Even it out with a spatula. Tap the pan lightly to get rid of the air bubbles.
Bake the cake for 25 minutes in the preheated oven. Turn up the oven to 240 °C or 464 °F and bake for another 10 minutes. The heat from ovens varies, so check on the cake to make sure the surface is slightly burnt. Add on the baking time by every 5 minutes if necessary.
The cake will be slightly jiggly, but that is normal. Let the cake sit in the pan until room temperature. The cake will fall drastically during this time. Do not remove it from the mold yet.