Traditional Cantonese Brown Sugar Steamed Sponge Cake

Place 100g brown sugar and 20g white sugar in a measuring cup, pour in 100g hot boiled water and stir until fully dissolved, add 250g cold water to cool down, then strain through a mesh sieve into a large bowl.

Add 5g high-sugar tolerant instant yeast to the cooled sugar syrup, and stir with a whisk until completely dissolved.

Add 180g tapioca starch and 240g all-purpose flour into the bowl. Whisk until fully smooth with no flour lumps, creating a pourable batter.

Cover the bowl with a lid and let it ferment at room temperature (about 26°C) for 1 hour, until the batter doubles in size and the surface is full of bubbles.

Sift 5g aluminum-free baking powder into the fermented batter and stir well. Add 20g corn oil and stir vigorously clockwise to thoroughly deflate the batter until smooth, glossy, and free of large air bubbles.

Grease an 8-inch cake pan with 5g corn oil on the bottom and sides. Pour the batter in and tap the pan several times on the counter to release trapped air bubbles. Place in a steamer over boiling water, cover, and steam on high heat for 10 minutes, then low heat for 20 minutes. Turn off the heat, let sit for 1 minute, then quickly remove the lid.

Cool the cake until slightly warm and safe to handle. Place the cake pan over a jar taller than the mold, push down to release the outer ring, and remove the bottom base. Transfer to a cutting board and cut into triangular wedges to serve.