Spread out cooking paper in the pan. Combine cake flour and cornstarch and sift. Preheat oven at 180℃.
Add eggs and granulated sugar into a bowl. Warm the bowl over a hot water bath and whisk well until thick.
Remove the bowl from the hot water bath midway and continue to whisk (for ideal thickness, refer to the photo - any markings should remain without disappearing). Beat at medium speed to finalize until really smooth.
Sift in the cake flour and swirl around for 2 to 3 minutes at low speed. Any large bubbles should disappear at this point. Beat until the batter is smooth and creamy.
Pour into the pan. Drop the pan onto your workplace for a couple of times to remove any air bubbles.
Bake for approx. 12 minutes at 180℃. When done, immediately drop the pan from a decent height onto your workplace. This prevents any shrinking.
Cover loosely with plastic wrap. If you're planing to flip over the sponge, cover tightly to cool down. The brown part will peel off nicely when removing the wrap.
Making the cream: Add heavy cream, granulated sugar, and brandy into a bowl and whip until stiff.
Spread the cream onto the sponge. Place the strawberries and a heaping amount of the whipped cream to your near-side. Roll it up to fold in.
Roll up little by little. As you do this, slowly remove the parchment paper.
Wrap in plastic (or a baking sheet) and chill in the fridge for half a day. This makes the sponge really moist and easier to slice.
Decorate with topping to finish.
Story Behind this Recipe
I really struggled to put together the ratio or the combination of the cake flour to make this without adding any liquid ingredients. I've finally managed to finalize the recipe after so much trial and error.
You might think that the batter will sink if you add the cake flour and use a hand mixer in step 4. Yet, this removes any excess bubbles and makes the sponge really fluffy and airy. Using a spatula takes too much time. If you're not going to flip the sponge over, there is no need to remove the browned surface in step 7.