Mix together both flours in a bowl.
Mix the jaggery with one-fourth cup of yogurt and whisk till the jaggery dissolves completely. Add to the flour mixture along with the carom seeds, chilli powder, turmeric powder, salt and two teaspoons of oil. Mix well. Add the remaining yogurt and knead into a semi-soft dough.
Divide the dough into eight equal portions and roll out each one into a thick chapati.
Heat a non-stick tawa, place a chapati on it and cook for a minute. Flip it over and drizzle a little oil all around. Cook till the underside is done. Flip it over again, drizzle a little more oil around and cook till both sides are evenly cooked.