Prepare the Batter: In a bowl, mix the glutinous rice flour, cornstarch, granulated sugar, and milk until smooth. Strain the mixture to ensure a finer texture.

Prepare for Steaming: Cover the mixture with plastic wrap to prevent water droplets from getting in, and poke a few small holes in the wrap with a toothpick to let the steam escape.

Steam: Place the covered mixture in a steamer and steam over medium-high heat for 25 minutes.

Add Butter: Once steamed, add the butter while still hot. Mix thoroughly with a silicone spatula until fully incorporated. Let it cool slightly before handling.

Knead: When it’s cool enough to handle, put on gloves and knead the dough for about 5 minutes, stretching and pulling until it becomes elastic. This step is essential for the perfect mochi texture.

Sprinkle some coconut flakes on your work surface. Place the mochi dough on top and roll it out into a thin rectangle using a rolling pin.

Spread the purple sweet potato paste evenly over the dough with a silicone spatula.

Roll the dough up from the bottom.

Use a piece of string to cut it into evenly sized pieces.