Preheat your oven to 350°F (175°C) and lightly grease a doughnut pan.
In a mixing bowl, combine the sweet rice flour, granulated sugar, and baking powder. Mix well to ensure there are no lumps.
In another bowl, whisk together the milk, egg, vanilla extract, and melted coconut oil until fully combined.
Slowly pour the wet ingredients into the dry mixture, stirring until a smooth batter forms.
Carefully spoon the batter into the prepared doughnut pan, filling each mold about 3/4 full.
Bake in the preheated oven for 12-15 minutes, or until the doughnuts spring back when gently pressed.
Allow the doughnuts to cool in the pan for about 5 minutes before transferring them to a wire rack to cool completely.
While the doughnuts are cooling, prepare the glaze. In a small bowl, whisk together powdered sugar and water until smooth. If desired, add a few drops of food coloring to create vibrant colors.
Once the doughnuts are cool, dip the tops into the glaze, allowing excess to drip off.
Finish by sprinkling with colorful sprinkles if desired. Let the glaze set for a few minutes before serving.
Notes
Feel free to customize the glaze with food coloring and sprinkles.