These paper-wrapped sponge cakes are just like the ones you find at your local Chinese bakery. They are light and airy, not too sweet, and a perfect treat for any time of day.
Preheat oven to 350F. Line a 6-cup popover pan or tall jumbo muffin pan with parchment paper that extends over the rim.
In a large bowl, whisk together the egg yolks, vegetable oil, milk.
5 large egg yolks, 1/4 cup (60ml) vegetable oil, 1/4 cup (60ml) milk
Whisk in sugar, and vanilla.
2 Tbsp granulated sugar, 1 tsp vanilla extract
Sift in the flour and baking powder. Whisk again until smooth. Set aside.
3/4 cup (90g) cake flour, 1/4 tsp baking powder
Beat the egg whites on medium speed until frothy and add the cream of tartar.
5 large egg whites, 1/2 tsp cream of tartar
Gradually add in the sugar while beating. Continue beating until stiff peaks.
1/4 cup (50g) granulated sugar
Gently fold the egg whites into the egg yolk batter, 1/3 at a time until just combined. Divide the batter evenly into the prepared pan, filling about 3/4 full.
Bake for 20-25 minutes or until golden on top and a toothpick inserted into the center comes out clean. Immediately remove the cakes from the pan and lay them on their sides to cool on a cooling rack.
Notes
Leftovers can be stored in an airtight container at room temperature for 3-4 days or in the fridge for up to a week. Bring to room temperature before serving.