In a mixing bowl, combine chickpea flour, baking powder, cumin seeds, red chili powder, turmeric powder, garam masala, and salt.

Add the thinly sliced onions to the dry mixture. Mix thoroughly to ensure the onions are evenly coated with the flour and spices.

Gradually incorporate water into the mixture while stirring. The batter should possess a thickness sufficient to coat the back of a spoon. Begin with approximately 1/2 cup of water and adjust as necessary.

Add the chopped coriander leaves into the batter and mix once more.

Heat vegetable oil in a deep pan for frying, aiming for a temperature of around 170°C (340°F).

Using a spoon or your hands, deposit small portions of the batter into the hot oil, taking care not to overcrowd the pan.

Fry the bhajis for approximately 3-4 minutes or until they acquire a golden brown and crispy texture. Remember to flip them halfway through for even frying.

Once the bhajis are cooked to perfection, retrieve them from the oil using a slotted spoon and place them on a plate lined with paper towels to drain any excess oil.

Serve the onion bhajis while hot, accompanied by your preferred dipping sauce, such as mint chutney or tamarind sauce.