Step 1

Preheat oven to 160 °C (320°F) with the fan on (see note 2 if you don't have a fan function) and line the bottom of two 8x3 inch baking tins with baking paper without greasing the bottom. Leave the sides of the cake tins ungreased and bare (do not line with baking paper).

Step 2

In a bowl combine your flour, cornstarch, baking powder and salt. Mix until well combined (you do not need to sift it yet). Set aside.

Step 3

In a medium sized bowl add in the egg whites and white vinegar, and using a hand or stand mixer, whip on a medium high speed for 30 seconds until foamy. Gradually add in 1/3 cup of the sugar and then continue mixing for a further 2 minutes. Then turn your mixer down to low and mix for a further minute (about 4 minutes of mixing altogether). You should end up with stiff peaks (see note 3). Set aside.

Step 4

In a large bowl add in your remaining 1/3 cup of white sugar and warm water. Mix so that the sugar is coated in the water. Add in the egg yolks and vanilla, and with a hand or stand mixer, whip on a medium high speed for 4 minutes, and then turn the mixer down to low and mix for a further minute (5 minutes of mixing altogether). Your mixture should now be thick and you should be able to create ribbons with it when you lift it up with a spoon.

Step 5

Stream the vegetable oil into the egg yolk mixture while mixing on a medium speed. Mix until well combined.

Step 6

Add in half of your egg whites to your egg yolk mixture, and using a spatula gently fold together until just combined.

Step 7

Then sift in your dry ingredients, and gently fold through until just combined.

Step 8

Finish off by adding in the remaining egg whites and gently fold until just combined. You can use your spatula to break up any large chunks of unmixed egg whites but try not to push out too many of the air bubbles and do not overmix.

Step 9

Distribute the batter into your baking tins and then tap your baking tins lightly on your counter. Then run a thin knife or toothpick through the batter to remove any large air bubbles and then bake for 25 minutes. To test whether they're done, gently touch the tops and it should create a little indent which slowly bounces back.

Step 10

Once the sponges are done, immediately tap them on the counter from a height of about 10cm, and lay them upside down (while still in their baking tins) on a wire rack to completely cool (see note 4).

Step 11

Once cooled (about an hour later), run a thin knife around the edges to release the cakes from the cake tins, and then turn them out onto a wire rack.

Step 12

To make my cake layers look nice and neat, I gently rub my fingers around the edges and the top and that removes the dark crust on the sides and tops of the cake (see video for demonstration). I find the dark crust on sponge cakes are also what contain that slight eggy after taste sometimes, which is why I prefer to remove it.

Step 13

APPLY SIMPLE SYRUP: Combine the sugar and hot water together for the simple syrup and mix until the sugar is completely dissolved. Using a pastry brush, generously brush the top and sides of the sponges with the simple syrup (see note 5). I use about 3/4s of the simple syrup mixture in total.

Step 14

In a large bowl add in the whipped cream, icing sugar and vanilla. Whip until you reach stiff peaks. Be careful not to overwhip the cream.

Step 15

Place one sponge cake layer down, and cover the top with a thin layer of my raspberry jam filling.

Step 16

Place strawberries on top (I like to cut mine in half and place them upside down). Cover with generous amount of whipped cream and spread it out evenly with an offset spatula or knife.

Step 17

Place your next sponge cake layer on top and then cover with more whipped cream. Finish decorating with more strawberries on top. Enjoy!