Slice the white onions thinly and separate the layers. Also, remove the thick central part of each slice.
In a bowl, add the sliced onions and mix them well with your hands. This helps to release moisture from the onions, so no extra water is needed.
Add salt, crushed carom seeds, turmeric powder, and coarsely ground coriander seeds to the onions. Add ginger-garlic paste and chilli powder to the onion mixture. Mix everything well.
Add one tablespoon of rice flour to the mixture.
Gradually add gram flour (besan) to the onion mixture. Use only as much as needed to bind the onions. The batter should be thick and coat the onions well without being too watery.
Heat oil in a pan over medium-high heat. The oil should be hot enough for frying.
Once the oil is hot, reduce the heat to medium. Drop small portions of the onion mixture into the hot oil. You can drop them loosely or take a small clump and then release it.
Fry the bhajis until they turn golden brown and crispy. Stir them occasionally for even cooking.
(Optional): If using, slit green chillies and add a pinch of salt inside. Fry them.
Once the bhajis are golden brown and crispy, remove them from the oil and drain them on tissue paper to remove excess oil.
Serve the hot and crispy white onion pakoda with fried green chillies and your favorite sauce, chutney.
(Optional Tip): For extra crispy bhajis, you can partially fry them until slightly cooked, let them cool completely, and then fry them again until golden brown and crispy.