1. In a medium size nonstick pan, put the sliced onions. Let it become transparent.
2. Add crudely cut thin potatoes.
3. Mix it well.
4. In a bowl, mix the flours, salt and enough water to make a thin paste like liquid.
5. Add this paste to the onion-potato. Slowly keep mixing it on medium flame. When it is mixed well, reduce the flame and let it set for about 10-15 minutes.
6. Uncover once to see if it has set from down. Using a plate, turn the tortilla upside down and then cook it on the other side. It should be like a round cake. Before serving, cut it into 8 pieces. It can be eaten with tomato ketchup. It can also be eaten as a sandwich filling with bread.