Mix together wet ingredients such as the flour, glutinous rice flour, arrow root starch, sugar, baking powder & soda, and salt. Whisk together until well combined. Set aside.
On a separate bowl, mix together the wet ingredients such as coconut milk, apple cider vinegar, ube extract, & melted butter. Whisk until all ingredients are fully whisked together.
Pour liquid ingredients into dry ingredients. Using a rubber spatula, gently fold wet & dry ingredients together until all dry flour has dissolved.
Be gentle, and ensure that batter is not over mixed. Lumps on the batter is okay.