Soak 3 cups of lentils in water overnight.
The next day, blend the soaked lentils until they are smooth and creamy. If necessary, adjust the consistency with a little more water to make it moist.
Chop 3 dried chilies and 1 red onion finely.
In a pan, combine the blended lentil mixture, half of the soaked but uncooked lentils, 2 tablespoons of cornstarch, 1/4 teaspoon salt, 1/4 teaspoon ground cinnamon, 1/4 teaspoon sweet cinnamon, 2 cardamom pods, and chopped chilies. Mix well.
Let the mixture rest for a few minutes to allow it to absorb flavors. Adjust seasoning if needed by adding more salt.
Wet your hands slightly with water to prevent sticking and scoop out dollops of the mixture onto a flat surface. Shape them into small, boat-like structures (vadai).
Fry vadai in vegetable oil until golden brown on all sides. Adjust frying time based on desired crispiness.
Serve hot. Enjoy!