Mix together rice flour, black gram dal flour, soaked chana dal, curry leaves, red chilli powder, pepper powder and cumin powder, asafoetida and butter with enough water to form a soft dough.
Spread a clean cloth on the floor. Take a small ball of dough and pat small six- centimeter diameter discs on the cloth.
Make small holes on the discs with a toothpick. Similarly make all the thattais. Heat sufficient oil in a kadai and fry a few thattais at a time on a moderate heat till crisp.
Drain onto an absorbent paper, cool and store in air-tight tins.