Steamed Brown Sugar Sponge Cake

Position a large bamboo steamer or a large vegetable steamer over gently bubbling water, ensuring it is spacious enough to accommodate a 10-inch round cake pan.

In a large glass or metal container, whip egg whites until they become light and airy, creating a fluffy texture. Gradually incorporate sugar into the mixture while continuously whipping until stiff peaks are formed, indicating that the mixture has reached a stable state.

In another medium-sized bowl, combine egg yolks, milk, and vanilla extract. Using an electric mixer, blend the ingredients together until well combined. Then, quickly merge this mixture with the whipped egg whites until no visible streaks remain.

In a separate bowl, sift together flour and baking powder to create a smooth mixture. Immediately fold this dry mixture into the egg yolk mixture until well incorporated. Pour the batter into a 10-inch round cake pan.

Carefully place the cake pan into the steamer, making sure it is securely positioned. Steam the cake for approximately 25 to 30 minutes, or until a toothpick inserted into the center comes out clean and free of any remaining batter. Remove from heat and let cool on a wire rack