Light steamed sponge cake with airy, fluffy texture is a simple Chinese dessert. A family recipe with fresh, eggy flavor and gentle sweetness.
Prepare a steamer by bringing water to a gentle simmer on medium heat. Line an 8-inch round cake pan with parchment paper.
In a large bowl, beat eggs using a mixer on high speed until foamy, then gradually add granulated sugar. Beat until the mixture is pale and voluminous, about 5–6 minutes.
Sift cake flour, baking powder, and salt together. Add sifted dry ingredients to the egg mixture in two additions, folding gently with a spatula to avoid deflating the batter.
Stir in milk, vegetable oil, and vanilla extract just until smooth and incorporated; do not overmix.
Pour batter into the prepared pan and tap to release large bubbles. Place pan in steamer, cover with a clean towel under the lid to catch condensation, and steam on medium heat for 30 minutes. Test doneness with a toothpick; the cake is ready when it comes out clean.
Remove from steamer and let cool slightly before unmolding. Slice and serve warm or at room temperature.