Bánh Bò Mã Lai (Hong Kong Style Malaysian Steamed Sponge Cake)

This recipe is for the Hong Kong version (usually served during Dim Sum) of Ma Lai Koh which is apparently “lighter” in color compared to the Malaysian version. However, I’m wondering if this cake is even Malaysian…since this cake is sometimes also called steamed sponge cake (which is a Chinese cake). Can some please enlighten me…please?

Ingredients:
-300g basic pau starter (use all purpose flour instead of cake flour)
-240g sugar
-4 eggs (200g)
-60g cake flour
-1 tbs custard powder (optional)
-30g oil
-1 tsp double acting baking powder
-1/2 tsp vinegar
-dash of lye water (about ¼ tsp)

What to Do:
Mix together by hand, sugar and pau starter until sugar dissolves. Then add eggs one at a time, followed by the addition of oil, custard powder, flour, vinegar, lye and baking powder; mix until smooth. Grease an 8” cake pan with some oil. Steam the empty pan for 5 mins before pouring in batter. Steam cake on high heat, lifting the lid to release excess steam every 10 mins. until done (about 30-40 mins).