Steps: 1. Sift flour and custard powder together and set aside. 2. Whisk the eggs, salt and sugar together until light and fluffy.(Do the ribbon test: Use the whisk to spoon some batter, drip some into the mixing bowl. If it stay visible for a while then this is the right stage.) 3. Lightly fold in the flour into the egg batter. 4. Lastly fold in the oil. 5. Pour into a lined and greased 7inches cake pan. 6. Cover with foil and steam at high heat for 25mins. 7. Remove cake and cool on a wire rack.