Preheat oven to 350°F. Lightly grease a non-stick donut pan.
In a medium bowl, whisk together gluten-free flour, baking powder, and salt.
In a large mixing bowl, combine sugar, milk, eggs, vanilla, and oil until well mixed.
Gradually add dry ingredients to wet ingredients, mixing until just combined.
Transfer batter to a piping bag or plastic storage bag with corner snipped.
Pipe batter into donut pan, filling each cavity 2/3 full.
Bake 12-15 minutes until lightly golden and springy to touch.
Cool in pan 5 minutes before transferring to wire rack.
For glaze: Whisk powdered sugar and milk until smooth. Dip cooled doughnuts and return to rack to set. Add dye-free sprinkles or topping of choice.