- Sift plain flour, baking powder and soda bicarbonate powder, set aside.
- Heat up steamer with enough water and wrap the cover with a kitchen cloth to absorb water droplets from dripping onto cupcakes.
- Blend sugar, egg and condensed milk in a blender for about 2 mins till pale and fluffy. Transfer to a big mixing bowl.
- Add cooking oil and mashed bananas. Beat with a whisk for 2-3 mins till smooth and fluffy. Add vanilla extract and beat a further 3 mins.
- Add in flour mixture in a few additions till batter is well combined.
- Grease cupcake moulds with oil before filling to ¾ full with batter, then place a slice of banana on top of each cupcake.
- Steam banana cupcakes on high heat for 20-25 mins. When cupcakes are cooked, remove the steamer’s cover and let it continue to steam for 3 mins to help dries up the surface.
- Let cool on cooling rack and serve.