In a large bowl whisk egg, milk, melted butter, and vanilla until smooth.

In a separate bowl, whisk together glutinous rice flour, sugar, baking powder, and salt.

Pour wet ingredients into dry ingredients and mix until a soft dough forms. It should be smooth and pliable, not overly sticky.

Lightly flour a surface with a bit of glutinous rice flour. Roll the dough out to about 1/2-inch thickness.

Cut out donut shapes using a round cutter and a smaller cutter for the center. Re-roll scraps as needed.

Heat 2-inch-deep oil in a pot to 350°F (175°C). Fry donuts in batches for 2–3 minutes per side until golden and puffed. Remove and drain on paper towels.

Sprinkle with powdered sugar if desired and serve warm or at room temperature.