Preheat the oven to 180°C (356°F) and grease a donut pan with softened butter and lightly coat with corn starch (flour) (see note 1). Dust off any excess flour.

Mix the glutinous rice flour, baking powder, and salt in a medium sized mixing bowl.

In a separate bowl, mix the melted butter and brown sugar. Then whisk in the egg. Once the egg is mixed through, stir through the milk, pandan extract, and vanilla extract.

Add the wet ingredients from step 3 to the dry ingredients from step 2. Mix until combined and there are no lumps.

Place the batter evenly in the prepared donut pan. (see note 2). Then bake in preheated oven for 20 to 25 minutes, or until the tops of the donuts become lightly browned.

Once baked, remove from oven and allow to cool in the pan for 5 to 10 minutes. After this, remove donuts from the pan and allow to cool completely. (see note 3).

Melt chocolate in a microwave or using the double boiler method. Once melted, mix through the vegetable oil. Place the melted chocolate and oil mixture in a bowl wide enough to dip a donut in.

Dip each cooled donut in the chocolate mixture, shaking off any excess mixture. Place on a wire rack (glaze side up). Optional: Sprinkle the glazed mochi donuts with crushed biscuits before the glaze sets.