Cake kukus ketan hitam putih telur (Egg white & black glutinous rice steamed cake)

This was my first time dealing with black glutinous rice flour. I became interested in this flour after Ummu fatima posted about black glutinous rice flour cake again, again and again. It was so tempting. She also said that it was her family's favorite and always disappeared in no time. Was it that good? hmmmm ...*so curious*

Since I still had 215 gr of egg whites, I then didn't use her recipe that require whole eggs. I googled to get another recipes and found one at sajian sedap. This recipe called for 200 gr egg whites but I used up all my 215 gr. I also substituted the plain flour for another black glutinous rice flour and substituted coconut milk with oil. Last, I omitted the cream of tartar and food colouring.
I only have a small steamer. It only fit a 16 X 16 cm pan. So, I filled up that pan 3/4 full and place the rest of the batter in 4 individual cupcake silicone cases. 
This cake didn't rise high. I didn't mind with that because it was still light, spongy and tasteful. I wondered how it tastes with coconut milk, it must be more tasty, I have to try it someday ^^. I didn't know why this cake was not as black as Ummu fatima's cake. Was it because the egg whites or because my black glutinous rice flour was different (in quality) from hers?

Ingredients:
200 gr egg whites (I used 215 gr)
80 gr caster sugar
1/2 tsp cream of tartar (I didn't use it)
1/4 tsp salt 
2 drop purple coloring (I didn't use it)
50 gr black glutinous rice flour
50 gr plain flour (I used black glutinous rice flour)
30 ml coconut milk (I used oil)

Methods:
Grease and line the 16 X 16 cm square pan. Prepare 4 cupcake silicone cases. Heat the steamer. 
Beat egg whites and salt until foamy. Gradually add in sugar. Beat until  shiny and thick. Turn off the mixer.
Add in the flour while sifting a little at a time. Using a spatula, mix carefully until well blended.
Transfer a bit of the batter into a bowl. Fold in the oil slowly until well blended. Pour it back into the batter. Mix again slowly.
Pour into the pan. Steam for 15 minutes.

Enjoy!