In a small bowl, combine the cake flour and cocoa powder. Then, sift the flour mixture over a sheet of parchment paper to remove the lumps. Sifting over the parchment makes it easier to pour in later, but this is optional, so you may sift it in a separate bowl instead. Set aside for now.

Crack the eggs into a large bowl and give it a quick whisk to combine the yolks and whites before adding the granulated sugar. Whisk the eggs and the sugar together, then over a pot of boiling or hot water continue whisking until the temperature reaches 42°C/108°F. Then remove from heat.

Combine the butter, peanut butter, milk, and vanilla in a small bowl and let it sit in the water to melt while we whip the eggs. Be careful to not let water get in.

Using a hand mixer, whip the eggs on high speed for about 6-8 minutes, then lower the speed to the lowest setting and whip for 1-2 minutes. The mixture should be very light and more than doubled in size.

Sift the flour mixture again but this time evenly on top of the egg mixture. Then gently fold to combine. Be sure to scrape all the way to the bottom to get any dry flour that may have sunk, and be careful not to deflate the batter.

At this point, the peanut butter and butter should be melted. It’s okay if the peanut butter is not fully melted. Whisk the mixture a little just to combine it all, then using the same spatula you used to fold the batter, mix in about 4 tablespoons of batter into the butter mixture. Once mixed, pour evenly over the batter and fold to combine.

Prepare a cake pan lined with parchment paper. Pour the batter in a steady stream from about 30cm/1foot above the pan. Drop the pan onto the surface twice to pop any large air bubbles. Bake at 170°C/338°F for 30 minutes. When the cake is done baking, turn it out onto a cooling rack and let it cool completely.

While the cake is cooling, prepare the simple syrup. Simply combine the water and sugar in a pot and heat until the sugar has dissolved. Set aside to cool.

Next, make the whipped cream. In a large bowl, mix together the cream, sugar, and vanilla. Whip on high until stiff peaks form, then separate about one third of the whipped cream into a smaller bowl. This cream will be used for the outside frosting of the cake, so you can dye it however you like, then refrigerate until ready to use.

With the remaining whipped cream, flavor it with the strawberry jam. Prepare the peanut butter syrup as well by combining the peanut butter and simple syrup. At this point, the cake should be cool enough to begin to work with.

Cut cake layers of about 1cm to 1.5cm thickness. This will depend on how big you are making your cake, but for lunchbox cakes, I prefer to do 1cm thickness!

Start by lightly soaking the first layer of cake with some simple syrup. You don’t want it too wet, but just enough so the cake stays moist. Place some strawberry whipped cream onto the cake layer and even it out using a frosting spatula or palette knife, reaching about half a centimeter in height. Create a small swirl starting from the middle of the whipped cream, going outward as you turn the cake. Spoon some of the peanut butter syrup into the swirl we created. Repeat until you’ve finished all the layers.

With the remaining strawberry whipped cream, crumb coat the entire cake. Refrigerate for about 30 minutes to allow the cake to set. Afterwards, frost the entire cake with the whipped cream we set aside in step 9 and decorate how you like. I recommend refrigerating again so the cake can set again, but otherwise the chocolate peanut butter cake is done! 完成です！