To Prep
In a large bowl, combine all the flour ingredients. Pour in oil while using your other hand to slowly knead. Then, gradually pour in water while continuing to knead and mix, getting rid of any lumps until a smooth, watery batter is obtained.
To Cook
Prepare a steamer over high heat. Using a rectangular tray, lightly brush it with oil. Slowly pour in a thin layer of batter to cover the tray. When the water is boiling, place into the steamer and steam for 2 mins. Then, add 2 tbsp of prawns on top of the rice roll in a straight line, about 3cm from the front edge of the rice roll layer. Sprinkle 1 tbsp green onions. Continue to steam for another 2-3 mins until prawns are cooked.
Remove from steamer and allow to cool for 2 mins. Roll the rice roll layer from the front edge to cover prawns and green onions. Repeat Step 2 and 3 with remaining batter.
Mix sauce ingredients into a bowl and pour over steamed rice rolls. Garnish with spring onions and serve with some XO sauce.