Soak lotus stems in water in a bowl for some time, then peel them and cut into thick slices.
Take 2 tbsps rice flour in a plate, add a little red chilli powder and salt and mix well. Roll the lotus stem slices in it till they are well coated.
Mix together 1 cup rice flour, remaining red chilli powder, cumin seeds, carom seeds, salt and little water in a mixing bowl to make a medium thick batter.
Heat sufficient oil in a kadai. Dip the lotus stem slices in the batter, slide into hot oil and deep fry till golden. Drain on absorbent paper.
Transfer into a serving platter, sprinkle chaat masala over them and serve hot.