Japanese cheese cake - fluffy & soft texture

The first time I tried a cheese cake, it failed, not strong flavor.... so I was afraid to make the cheese cake again, until I found a lemon cheese cake recipe, I loved it so much. Recently I found another recipe to make Japanese cheese cake, with fluffy & soft texture, that is why I want to give it a try.

Ingredients
250g milk
250g cream cheese, room temperature
60g butter, room temperature
6 egg yolks

55g cake flour
20g corn flour
1 lemon zest

6 egg whites
1/4tsp cream of tartar/powder of tartar (optional)
130g sugar

Instructions
1. Pour milk and put cream cheese in a bowl on simming water, cream cheese will melt. Try to mix well with milk. It takes some time until the cream cheese is dissolved into the milk. Add in butter, mix until totally melt into the mixture.

2. Turn off the heat, add egg yolks
Let the mixture cool down

3. Add in flour and corn flour, it is ideal to mix until no lumps, use spetula to help - press the flour towards the sides of the bowl
Add lemon zest

4. In another bowl, beat egg white until soft peak is formed
Add cream of tartar and sugar, beat until peak form

5. Pre-heat the oven at 150°c
Fold in egg white mixture in 2-3 times

6. Pour the mixture into a 8" mold, place mold on the tray and add hot water up to half of the mold*
Bake for 50-60mins
*Note: it is to help the bottom of the mixture cook well

7. Turn off the oven, open door a bit for 10mins**
Let it cool down, then put into the fridge for 3hours before serving
**Note: let some cool air in the oven can help to prevent the cake collapse completely

It is very light as texture :)

Enjoy!