Put 250 g wholemeal flour or chapatti flour, 0.3 g salt and 40.5 g vegetable oil in a bowl and stir roughly with a spoon.
Add 179 g water a little at a time, mixing after each addition, until the dough comes together.
Knead the dough with your fingers until it is smooth and firm but pliable; add a little more flour if it is sticky or a splash of water if it is dry.
Cover the dough and leave it to rest for 15 minutes.
Knead the dough again, then divide it into equal-sized balls.
Flatten each ball, rub it with a little oil and roll it into an 8 cm disc; keep the discs not too thin so they can puff.
Heat enough vegetable oil for deep-frying in a kadhai or wok, filling it about one-third full, and line a large bowl with paper towels.
Check the oil by frying a small square of dough: it is ready when it sizzles and browns in about 30 seconds.
Lower one puri into the hot oil; it will sink and then rise, so press it gently with a slotted spoon until it puffs, turn it and cook for 2–3 seconds on the second side until lightly golden.
Lift the puri out, drain it on the paper towels and repeat with the remaining dough.