Start by thinly slicing your ripe Pisang Awak bananas and placing them in a mixing bowl. Sprinkle with light brown sugar, ensuring all slices are coated evenly. Let this mixture marinate for 20-30 minutes.

In a separate large bowl, combine the tapioca starch, rice flour, salt, and optional cinnamon powder. Whisk together until thoroughly blended.

Slowly pour in the measured water into the dry ingredients while stirring gently until you achieve a smooth batter. Fold in the marinated banana slices, reserving some for topping later.

Set up your steamer by bringing water to a gentle boil. Wrap the lid with a clean kitchen towel to prevent condensation from dripping.

Pour the banana batter evenly into your greased mold and layer the reserved banana slices on top. Carefully place the mold into the steamer and cover with the lid. Steam for 25-30 minutes.

Once cooked, carefully remove the mold from the steamer and let the cake cool slightly for about 10 minutes. Slice and serve warm with coconut sauce and toasted sesame seeds.

Prepare the coconut sauce by gently heating canned coconut milk in a saucepan. Stir in salt and light brown sugar, then thicken with a cornstarch slurry, whisking until the desired thickness is reached.