Egg White Steam Rainbow Cake

I have plenty of egg whites left from my baking of lapis. I google for egg white recipe and this rainbow cake from bisousatoi caught my attention immediately. Ms Rima who is the owner of the said site has many recipes which I can't help but keep browsing through it. You can see how fluffy her rainbow cake is by checking out at the link.

Er...but mine turn out to be kueh...wonder if it could be due to the following reasons

1) water dripped into the batter while steaming?Am using high flame for steaming?
2) I have omitted ovalette and egg whites batter got deflated?
3) I have reduce the sugar by 50gm. sugar not enough? ( But 275gm of sugar is still too sweet to my liking)
4) Can see a bum at the Mocca layer??? Trapped air bubble?
5) Recipe call for 8' sq tin but I used 8' round tin. too small?

Hee...will need expert to troubleshoot for me =)

Overall the cake still taste good if not for the dense texture. I find it taste like 九层糕 .
Close up view of the cake texture. Mocca layer still taste fluffy. The worst layer is the strawberry

Recipe from Bisousatoi

Ingrident:
500ml egg white
325g caster sugar
1tbsp of ovalette
1/2 tsp of salt
100ml evaporated milk
50g melted butter or oil
1tsp of baking powder
200g flour
50g corn flour
25g milk powder
1tsp vanilla essence
1tsp strawberry paste
1tsp lemon paste
1tsp mocca paste
1stp pandan paste
Method:
1. Whisk egg white, sugar, salt , ovalette till light and fluffy (abt 10 mins)
2. Sift flour, corn flour, milk powder, baking powder and put it aside
3. Mix melted butter and evaporated milk and put it aside
4. Add in vanilla essence
5. Add in siged flour a litte at a time
6. Divide batter into 4 parts ( 320g each) and add each paste to each part
7. Prepare steamer ., greased a 8x8inch square tin
8. Steam 7 mins for each layer, come to the last layer, steamed for 15mins , let it cool, unmould and slice.