Preheat oven to 425 degrees. Generously grease a 12- or 24-cup mini-muffin pan or small dariole molds. Combine all ingredients in a large bowl. Mix well until batter is smooth. Fill each muffin cup three-quarters full. Bake for 15 minutes or until golden brown. Puffs should be crisp on the outside and hollow on the inside, like a popover. Serve warm.
*Sweet and sour tapioca flour can be found at Brazilian food stores.