Beaten the egg in a bowl and mix with the sugar. Mix until fluffy.
Gradually add the milk and oil to the bowl and mix until all the ingredients incorporate.
In a separate bowl, add all the dry ingredients and mix thoroughly.
Add the dry ingredients to the egg cream. Mix well.
Place a cupcake liner in heat-resistance ramekin bowl. Pour the filling into the bowl.
Put the bowl filled with matcha filling in a steamer and steam the cake for about 20 minutes.
Serve hot or cold on a plate with your favorite topping.