Separate egg yolks and egg whites into two separate bowls. Put the egg whites in the fridge
In a small bowl, whisk milk and oil until combined.
Sift in all-purpose flour and corn starch. Mix gently until combined.
Add egg yolks into the mixture. Mix until combined.
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 (20g) gradually and whisk at medium-low speed. After you add the last part of sugar, turn to high speed until medium peak forms.
Put 1/3 of the meringue into the yolk batter. Gently mix them until combine.
Gently mix the batter with the remaining yolk batter, until combine.
Bring out the ramekins from the oven. Do not remove them from the water bath. The pudding shouldn't be fully cooked at this point. Gently top the ramekins with the cake batter. The cake batter should be runny enough to pour directly, or you can use a piping bag.
Bake with the water bath for 20 minutes at 140 °C or 293 °F. Then increase the heat to 155 °C or 311 °F and bake for another 35 minutes or until the surface turns golden brown.
Once it is baked, turn off the oven and leave a gap open. Let the pudding cake rest for 5 minutes before bringing them out.
You can eat directly from the ramekin. Or use a small sharp knife to loosen the pudding cake from around the sides of the mold to remove from mold.