Preheat the oven to 150 °C or 300 °F.
Separate egg yolks and egg whites into two separate bowls. Put the egg whites in the fridge. (see tip #1)
Sift all-purpose flour, black sesame powder, and corn starch. (see tip #2)
Add sugar (12g) into the egg yolks. Whisk until sugar is dissolved and the batter becomes yellowish-white. (see tip #3) Whisk in oil.
Sift the flour, black sesame powder, and corn starch again. Slowly add the dry ingredients interchangeably with milk into the yolk batter. Use a spatula and mix until everything is combined with no lumps. Do not over-mix it. Set aside. (see tip #4)
Bring out the egg white from the fridge. Whisk the egg whites at low speed, allowing small stabilizing bubbles to form. Add in the sugar (30g) gradually and whisk at medium-low speed. After you add the last part of sugar, turn to high speed until stiff peak forms. (see tip #5)
Put 1/3 of the meringue into the yolk batter. Gently mix them until combine. (see tip #6)
Gently mix the batter with the remaining yolk batter, until combine.
Pour the batter into the mold (see tip #7 & 8). Tap the pan lightly to get rid of any trapped air bubbles in the batter. (see tip #9)
Bake for 15 minutes at 150 °C. Then bake for 20 to 25 minutes at 175 °C.
Once it is baked, bring the cake out immediately and tap the cake pan lightly a few times to release the hot air. Turn the cake pan upside down on a cooling tray for at least 45 minutes. Do not remove the cake from the cake pan at this point. (see tip #10)
After 45 minutes, you can remove the cake from the pan. Serve with the black sesame whipped cream.