Sponge Cake

• Step 1: Prepare the Egg Yolk Mixture

Combine the Hoa Ngoc Lan No. 11 wheat flour, cornstarch, and white sugar in a mixing bowl. Add the egg yolks, whole egg, unsweetened fresh milk or water, and cooking oil. Whisk until the mixture is smooth and thick. Strain through a sieve to remove any lumps.

• Step 2: Whip the Egg Whites

Place the egg whites in a clean mixing bowl. Add the salt and lemon juice, then beat until foamy. Gradually add the 50 g of white sugar while continuing to beat. Whip until soft peaks form: when the beaters are lifted, the peaks should gently bend over.

• Step 3: Fold the Mixtures Together

Add a portion of the whipped egg whites to the egg yolk mixture and gently fold to lighten the batter. Add the remaining egg whites and continue folding with a spatula, using an upward motion from the bottom of the bowl until just combined. Avoid overmixing to preserve the air in the batter.

• Step 4: Prepare the Pan and Preheat the Air Fryer

Preheat the air fryer to 150°C. Pour the batter into an 18 cm round cake pan or a suitable chiffon cake pan. Do not overfill the pan.

• Step 5: Bake the Cake

For an 18 cm round cake pan: Bake at 150°C for approximately 80 minutes, following the original recipe.

For smaller aluminum or paper molds: Bake at 140°C for approximately 70–80 minutes, as specified in the original recipe. Smaller cakes may bake faster, so check for doneness during baking.

The cake is ready when the center is set and a toothpick inserted into the middle comes out relatively clean. If the top browns too quickly, adjust the temperature or cover the top with a heat-safe material approved for use in the appliance.

• Step 6: Cool the Cake

Remove the cake from the air fryer and allow it to cool. If using a chiffon cake pan designed for inverted cooling, turn the pan upside down while the cake cools to help minimize shrinkage.