Prepare cake mold and place baking paper or banana leaf on the bottom for later use.

Add enough water to the steamer and turn on the heat to preheat the steamer.

Pour the corn oil into the bowl first, then put the banana into the bowl and mash it with a fork.

Separate the yolks and whites of the eggs, and put the yolks in a bowl of corn oil. Put the egg whites into a large bowl that is free of oil and water.

Add in water and salt into yolks and stir well.

Add sifted all purpose flour and corn starch then mix well.

Add lemon juice or white vinegar to egg whites.

Beat with a whisk at high speed until there are large bubbles formed, add 1/3 fine sugar, and then continue to beat at high speed.

After the bubbles become thinner, add 1/3 fine sugar, and then continue to beat at high speed.

After the bubbles are finer, add the remaining fine sugar, and continue to beat until stiff peaks.

Scoop the meringue into the egg yolk batter in 3 portions and mix well.

Pour the evenly mixed batter into the mold, tap it a few times to knock out the large air bubbles.

After steaming, use a knife to cut along the edge of the mold, pull out the baking paper and cut it into the size you like.