Prepare two clean bowls, free of water and oil. Crack the eggs into one of the bowls and set it aside. The other bowl will be used for the batter.

Pour 30g of cooking oil and 40g of full-fat milk into the empty bowl. Use a whisk or chopsticks to stir until the oil and milk are fully emulsified, forming a smooth, uniform mixture.

Sift 60g of low-gluten flour into the emulsified liquid, and gently stir with a spatula. Be careful not to overmix, just until the flour is fully combined with the liquid and there are no dry flour spots.

Separate the egg whites and egg yolks. Add the egg yolks into the batter and mix well. If the batter is too thick, you can add a small amount of milk to thin it slightly. The batter should be smooth and drop in a smooth, stacking manner from a height.

Add a few drops of white vinegar to the egg whites to reduce any odor.

Add 40g of white sugar, and start whipping the egg whites with a low-speed mixer to create large bubbles. Gradually increase to medium speed until the egg whites become finer with distinct lines, then switch to high-speed to whip until the egg whites form stiff peaks, where the peaks stand straight when the whisk is lifted.

Take one-third of the whipped egg whites and fold it gently into the batter using a spatula, moving from the bottom to the top. Be quick and light-handed to avoid deflating the mixture.

Once well mixed, pour the batter back into the remaining egg whites and continue folding until fully incorporated

Pour the mixed batter into the 6-inch chiffon cake mold. Tap the mold gently on the countertop to remove any large air bubbles.

Cover the mold with two layers of plastic wrap and tie the wrap tightly with string (this step is optional but helps prevent steam from entering the mold during steaming).

Add enough water to a steamer and bring it to a boil over high heat. Once boiling, place the mold with the batter into the steamer. Reduce the heat to medium-low and steam for 45 minutes.

During steaming, keep an eye on the water level in the steamer to avoid it running dry, which could cause the cake to shrink.

After 45 minutes, check if the cake is fully steamed. Remove the mold from the steamer immediately, take off the plastic wrap, and gently tap the mold again to release any excess steam.

Invert the mold onto a cooling rack and let the cake cool naturally. Handle quickly but gently. Once the cake has cooled completely, it should easily release from the mold. Enjoy your delicious steamed cake!