In a mixing bowl, combine the 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 well, ensuring the onions are coated evenly with the flour and spices.
Gradually add water to the mixture while stirring. The batter should be thick enough to coat the back of a spoon. Start with about 1/2 cup of water and adjust as needed.
Add the chopped coriander leaves to the batter and mix again.
Heat vegetable oil in a deep pan for frying. The oil should be around 170°C (340°F).
Using a spoon or your hands, drop small portions of the batter into the hot oil. Be careful not to overcrowd the pan.
Fry the bhajis for about 3-4 minutes or until they turn golden brown and crispy. Make sure to flip them halfway through for even frying.
Once the bhajis are cooked, remove them from the oil using a slotted spoon and place them on a plate lined with paper towels to drain excess oil.
Serve the onion bhajis hot with your favourite dipping sauce, such as mint chutney or tamarind sauce.
