Step 1: Spray an 8" round pan with Pam and line the bottom with a circle of parchment
Beat 3 eggs and brown sugar in a mixer on med-high speed for 5 minutes.
Meanwhile, prepare your steamer.
Step 2: Preheat the steamer by bringing the water to a boil with the lid on. Add the coconut milk, vanilla and melted butter to the egg mixture and beat for 1 minute.
Step 3: Sift the flour, baking soda and baking powder in a bowl. Resift the flour mixture over the prepared batter. Using a balloon whisk, gently but quickly fold in all the flour so that the batter does not deflate; yet all the flour is combined.
Step 4: Pour the batter into the prepared pan. Lightly cover the pan with foil and place the pan on the steaming rack. Cover with the wok lid.
Step 5: Steam for 30 minutes over high heat. CHECK THE WATER LEVEL PERIODICALLY to ensure that you don't boil away all the water.
Step 6: Add sufficient hot water to maintain water level just below the bottom of the pan. Remove pan and cool the cake; slice and serve.