Vietnamese steamed banana cake | Bánh chuối hấp

Ingredients:\r
6 ripe bananas\r
1 1/2 cup of rice flour\r
1 1/2 cup of tapioca starch\r
1 1/2 cup of water\r
1/2 cup of sugar\r
1 teaspoon of banana flavoring\r
yellow food coloring\r
cooking oil\r
coconut cream:\r
1 can of coconut milk\r
3 teaspoon of tapioca starch mix with 2 table spoon of water\r
5 table spoon of sugar\r
1 pinch of salt\r
some minced scallion