• Spray the baking pan, 9 x 13 x 1 inch, with non-stick cooking spray or brush some oil and then line with a parchment paper on the bottom and the side

Prepare the cake batter:

• Preheat oven to 350 F (180 C) for a conventional oven. Lower the temperature by 20 degrees for a convection oven. In a large mixing bowl, whisk egg yolks, oil, and milk until combined. Sift in the cake flour, and salt. Whisk to mix until combined and no lumps

Prepare meringue:

• Make sure the egg whites are at room temperature. Place egg whites in a mixing bowl of a stand mixer fitted with a whisk attachment. Whisk until foamy on medium speed and then add cream of tartar or lemon juice/vinegar and whip again for another minute then and 1/3 of the sugar and continue to add sugar until you use it all up. Whip until the egg white develops a medium-soft peak (refer to video if you need to). When you lift the meringue up it will hold up its shape but the tail will bend. Do not whip until stiff peak. The cake will crack when you roll it later

Fold meringue into cake batter:

• Fold about 1/3 of the meringue into the egg yolk batter and use a rubber spatula or whisk to fold or whisk until mix and continue to fold in the next 1/3 until you use up all the meringue and the batter is smooth . The batter should be a pourable consistency

Pour into baking pan (9x13x1 inch):

• Pour the batter into the pan and use a rubber spatula to help to spread evenly. You can use a dough scraper to help you even out the surface too if necessary

Bake:

• Gently tap the baking sheet on your working surface several times to pop any air bubbles
• Bake in a preheated oven for 30 minutes and then switch to convection mode (fan mode) and bake for another 3-4 minutes or until the top is golden brown and dry to touch. If you don't have convection mode, bake another 5 minutes and check to make sure the top is golden brown and dry to touch. It is important that the top is dry to touch so this layer won't peel off when you roll later

Cool down:

• Remove the cake from the oven and then lift it out from the pan immediately to a cooling rack and peel off the parchment paper from 4 sides. This helps to prevent wrinkles on the surface. Let it cools down like this for 5-6 minutes (I use a timer to actually time it)
• After 5-6 minutes. Place a new piece of parchment paper, larger than the cake, on top of the cake and flip over to the other side. Peel off the parchment paper

Trim the 4 edges:

• Use a serrated knife to trim about 1/4-inch of the 4 edges. This makes rolling the cake easier.

Make 4 shallow slits on the cake:

• Use a serrated knife to make 4 shallow slits. about 1 inch apart, taking care not to cut through the cake. This makes rolling the cake easier

Spread the filling:

• Spread the kaya jam on the surface of the cake. You want to spread most of the filling near the side you are going to roll up from and there should be less filling towards the other end because as you roll up, the filling will get push forward and by the time you roll to the other end, it is just a perfect amount of filling

Roll up the cake:

• Very gently use one hand to lift the parchment paper up to help you roll the cake up until you reach the other side. Tuck the parchment paper under and use a dough scraper to help you tighten the roll up

Remove the parchment paper immediately:

• Now, most people will keep it rolled in a parchment paper this way and store it in the fridge to let it chills for 2-3 hours before slicing. I don't want to do that because the skin will peel right off after that (trust me, I've baked more than 10 Swiss rolls to figure this part out lol). Why? because our cake is still very slightly warm when we rolled it and then the fridge is cold and the condensation will form and makes the skin wet
• Instead, remove parchment paper. Very gently place the cake on the serving plate you plan to serve. You can seal both ends with a bit of kaya. This helps to prevent the cake from drying. Loosely tent with a parchment paper, not touching the surface of the cake. Store in the fridge for at least 1 hour before you plan to cut the cake. I keep it in the fridge like this until the next day and the cake is perfectly moist and the skin is intact

Serve:

• Trim off about 1/4 inch from both ends (my kids are happily eating those trims) and then slice the cake into slices in whatever size you like

How to store:

• Keep any leftover in the fridge, covered with wrap for maximum one week