Separate the egg yolks and whites, placing them in two clean, dry bowls. Ensure no yolk is left in the egg whites, as this will affect the whipping process.

In the bowl with the egg yolks, add the milk and corn oil, mixing until well combined.

Sift in the all-purpose flour, glutinous rice flour, and millet flour, then add the black sesame seeds. Stir until you achieve a smooth, fine batter.

If desired, add lemon juice to the egg whites. Using a mixer, whip the egg whites at medium speed.

Gradually add the sugar in two to three stages while continuing to whip until you achieve stiff peaks.

Gently fold one-third of the whipped egg whites into the egg yolk mixture using a spatula. Be careful not to stir in circles, as this can deflate the egg whites. Repeat until all the egg whites are incorporated.

Pour the batter into two 6-inch cake molds.

Steam over boiling water for 40 minutes, ensuring there’s enough water in the pot to prevent it from drying out.

Once steamed, gently tap the molds on the counter, then invert them to cool before removing the cakes.