Heat a few tablespoons of oil in your frying pan or wok over medium heat, and toast the cumin seeds until fragrant, about 30 seconds. Remove and set aside.
Meanwhile, peel and finely slice the onions, aiming for thin, uniform slices that will fry evenly and become crispy.
In a large mixing bowl, combine the chickpea flour, chili powder, toasted cumin seeds, and a pinch of salt, stirring well to distribute the spices evenly.
Add the sliced onions and chopped green chilies to the flour mixture, then pour in 4 tablespoons of water to start binding the ingredients.
Gradually add more water, about 1 tablespoon at a time, mixing until you have a thick, sticky batter that coats the onions well. Adjust with more flour or water if needed.
Once the oil reaches 180°C (356°F) — check with a thermometer — carefully drop spoonfuls of batter into the hot oil, about 2 tablespoons per fritter, avoiding overcrowding.
Fry the bhajis for 3-4 minutes, turning occasionally, until they are golden brown and crispy on all sides, with a crackling sound as they fry.
Use a slotted spoon to lift out the fried bhajis, draining excess oil, and transfer them to a paper towel-lined plate or wire rack.
Repeat the frying process with the remaining batter, maintaining the oil temperature and frying in batches.
Serve the onion bhajis hot, with lemon wedges or chutney, and enjoy the crispy, fragrant bites that capture the warm aroma of fried onions and spices.
