In a mixing bowl, combine sweet rice flour, sugar, and water, stirring until smooth, and pour into a heatproof dish.

Set up a steamer, bring water to boil, place the dish with batter inside and steam for about 20 minutes.

Remove steamed mochi and let cool slightly; add oil and optional dragon fruit juice, then knead for 5 minutes.

Dust hands with cornstarch, shape small pieces of dough, place banana in the center and seal.

Roll each mochi in coconut flakes until fully coated, then place on parchment-lined baking sheet.

Optionally dust with powdered sugar and serve at room temperature for best enjoyment.