This is an Indonesian cake that is known as Pepe Panggang. Indonesia has a very famous layer cake called Lapis Legit which is spekkoek flavored and uses at least 30 yolks, so when they bake lapis legit, they have tons of egg whites left and often used to make this cake.
Step 1: Ingredients and Method
500 ml egg whites
250 g sugar
1 tbsp cake stabilizer such as Ovalet (available at Asian stores or online)
250 g flour mixed with a pinch of salt
300 ml coconut milk (canned, not coconut milk beverage)
1/2 tsp cocopandan essence (available at Asian stores or online, if not use raspberry/strawberry essence with a drop or two red food coloring)
1/2 tsp pandan paste (available at Asian stores or online, if not just use green food coloring)
Beat egg whites until foamy and fluffy, add in sugar a little at time while keep beating, and keep beating until thickened/firming
Add ovalet while keep beating, and beat for 2 minutes long
Turn off mixer, add in a little coconut milk, stir with spatula then add in a little flour, stir. Repeat this step until coconut milk and flour all used up and mixed well.
Divide batter into 3 equal portions. One leave it as is while the other two, mixed with cocopandan essence and pandan paste.
Preheat oven to 350 F, grease a rectangular pan (20x29x4), lay a parchment paper on it and grease the paper as well.
Pour 1 cup of regular batter, spread evenly and bake for 5 minutes. Pour the next color for a cup as well, and bake for 5 minutes, follow with the last color. Repeat step, each time one cup and 5 minutes, so you are making layers.
Once all batter used up, bake the whole cake for 20-25 minutes.
Cool to room temperature and slice.