Pre-heat oven to 200°C (Top and bottom heat, no fan force)
Line bottom of the cake pans and grease the sides.
Whisk cream cheese and butter till smooth over a water bath or can do double boil method.
Add the sugar (70g) and whisk until dissolved. Remove from water bath
Add cold milk and whisk until combined.
Add egg yolks one at a time and whisk until smooth.
Add vanilla, salt, lemon juice, lemon zest and whisk
Sift flour and fold into mixture. Set aside.
Whisk whites at low speed till foamy
Add cream of tartar and beat at high speed till bubbles become very small but still visible
Gradually add sugar (70g) and beat till just before soft peaks
Fold whites into batter 1/3 at a time. Set aside a couple of tablespoons. Divide batter into 2 portions and add 2 tablespoons of cocoa powder into one portion together with the reserved meringue. Gently fold until combined.
Pour both batter alternately into prepared pan and tap the pan on the counter to release air bubbles
Bake on the lowest rack in a preheated 200 degree C oven (top and bottom heat, no fan force) for 18min, lower to 160 degree C for 12 mins and turn off the oven and leave cake in the closed oven for 30 mins. Open the door of the oven slightly at the end of the baking for 10 mins for cake to cool.