Uh, please don't laugh, but we Indonesians do confuse breads and cakes. Although "roti" usually refers to yeast bread, this cake also has a "roti" in its name despite the absence of yeast.
3 egg yolks
1 egg white
180 gr caster sugar
180 gr plain flour
100 ml sprite
1 tbsp cocoa powder
1. Prepare steamer. Line roti kukus moulds with parchment paper.
2. Beat egg yolks, egg white, and caster sugar until thick and pale.
3. Fold in 1/3 of the flour, then 1/2 of the sprite. Gently mix. Repeat with remaining flour and sprite, ending with flour. Mix thoroughly until there is no lumps in the batter.
4. Divide 1/3 of the batter into a small bowl and add cocoa powder. Whisk until thoroughly combined.
5. Spoon white batter into moulds. Swirl a little of the chocolate batter. Steam for 15-20 minutes on high heat.
- it is ok to steam the cakes in several batches - it is best to steam them in small quantity at a time. Unlike common cake batters which should be baked immediately, this batter can stand quite long. (However please don't leave the batter while you watch movies or so - I don't guarantee they'll be still good after such a long time!)
- do not open the steamer at the first fifteen minutes. Peeking can cause the rising of the cake to stop, just like when we bake pate choux or souffle. (thanks Tuty for the addition!)
- I've seen other people using usual muffin moulds for this cake and it turns nice too... I haven't tried it myself, though.
- My dad loves the chocolate part more than the white one (who doesn't, by the way?), so sometimes my mom divide the batter into two equal parts and add 3-4 tablespoons for the chocolate batter.