In a large bowl, add sliced onion, potato, spinach, eggplant, green chilies, and chopped coriander.
Add salt, red chili powder, coriander powder, cumin seeds, garam masala, black pepper, fennel seeds, and ajwain. Mix well.
Add gram flour (besan) and mix with the vegetables.
Gradually add a little water to make a thick batter that coats the vegetables.
Heat oil in a deep pan over medium heat.
Drop small portions of the mixture into the hot oil.
Fry for 4–5 minutes until golden brown and crispy.
Remove pakoras and place them on paper towels to remove excess oil.
Serve hot with mint chutney or ketchup.