Rinse the lentils for a couple of times and then soak in enough water for at least 6 hours. For a quicker option, you can heat water and then soak the lentils in the hot water for an hour.
When lentils are fairly soft from soaking, add the following whole spices – dry red chili, fennel seeds, coriander seeds and black pepper. Grind the spices using a food processor, blend the lentils coarsely.
After spices are ground, add the chopped onion, green chili, ginger, curry or mint leaves, coriander leaves and a pinch of garam masala and salt to taste. Mix very well.
Shape to medium sized balls and then flatten them to form patties. If mixture is too soft, then add 1 or 2 tbsp of rice flour.
Heat oil for deep frying in a pan on a medium flame. Check the oil temperature by dropping a small portion of the batter in the oil. If it comes up steadily, the oil is hot enough for frying.
Carefully slide the patties in the hot oil. Fry them for a couple of minutes on one side and then turn over with a slotted spoon and fry the other side.
When patties become golden and crisp, remove from pan and drain them on paper towels.
Serve with chutney or mint yogurt sauce, as a vegetarian burger for non-celiacs, or with tamarind vegetable soup and rice for celiacs.