Mix dry ingredients: Combine rice flour, urad dal flour, plain flour, salt and baking soda in a bowl. Mix well.
Add oil and water: Add the oil and gradually add water to form a dough.
Knead: Knead until you have a firm dough that holds together.
Shape large balls: Divide the dough into roughly equal large balls.
Boil: Place the dough balls in boiling water and cook for 10–12 minutes. Remove and allow to cool enough to handle.
Knead again: Break up the cooked dough, add cumin seeds and white pepper, and knead again until smooth and workable.
Cut: Roll the dough into long cylinders and cut into small, equal-sized pieces.
Shape and oil: Roll each piece into a small round ball and toss lightly with oil.
Preheat: Preheat the air fryer to 150°C (300°F). Arrange the seedai on the air fryer tray in a single layer.
Air fry: Cook at 150°C for approximately 25 minutes, spraying oil three times during cooking.
Cool: Remove when golden brown and allow to cool completely before serving or storing.