Vietnamese Sponge Cake Banh Bong Lan

I am not a professional baker, but this simple Vietnamese sponge cake is quite easy to make because it does not require a high skill to make. In Vietnam, street vendors baked this cake in a cast iron mold with charcoal covering the entire mold, and the cake came out very light, soft, and with a bright color from the egg yolk. As a young girl, I watched them make this cake from the beginning to the end with great admiration. Later, I learned that the secret comes from beating the egg white until it stiff peaks, and lemon juice plays a big role in this process. I tried different recipes for sponge cake, and finally this one came very close to the Vietnamese sponge cake sold by street vendors in Vietnam.

Ingredients:
4 large eggs, separated
1/4 tsp sat
1 1/2 tsp lemon juice
1/2 cup sugar
1 cup cake flour
1/4 cup milk, room temperature
1/4 cup vegetable oil
1 tbs vanilla

Directions:
Preheat oven set to375°. Line the bottom of a 9 inch round or square cake pan with parchment paper. Spread butter over the entire bottom of the cake pan.
Place the white of four eggs in the bowl of a KitchenAid® stand mixer. Add salt and lemon juice and 1/4 cup of sugar. Attach the whisk and turn the machine to medium. Start beating the egg white until it stiff peaks (about 10 minutes).
In another bowl, combine egg yolks,1/4 cup sugar, and vanilla and beat until well combined. Add milk, oil and continue whisking mixture. Sift haft of the flour into the egg-milk mixture . Continue to mix until incorporated.
Take half of the egg white mixture and fold into the egg yolk mixture until there is no trace of the egg white. Pour this mixture into the other half of the egg white mixture; add the rest of the flour. Gently mix them together until well combined. Pour the batter into the prepared cake pan. Bake in the oven for 30 minutes.

 Let cool and serve with blackberry jam