Wash the chana dal well and soak it in plenty of water for about 1 hour. Soak the almonds in the same bowl.
Drain the dal and almonds thoroughly, then leave them in a colander for a couple of minutes. The less water left on the dal, the easier it will be to shape the vadai.
Add the drained dal and almonds to a mixer jar with the red chillies, curry leaves and salt. Grind to a coarse batter without adding water.
The mixture should have some texture. Do not grind it into a smooth paste. If the mixer needs help, add only 1 tablespoon of water and continue grinding. A soft or watery batter will make flat, oily vadai instead of crisp ones.
Transfer the ground batter to a wide bowl. Add the chopped cabbage, coriander leaves, ginger and hing.
Mix everything well with your hands. The cabbage should be evenly distributed through the batter, and the mixture should be firm enough to shape.
Heat oil in a wide, deep pan over medium heat. Take a small portion of batter and flatten it into a thin round patty between your palms.
Keep the vadai fairly small and not too thick; thin patties cook evenly and turn much crisper.
Gently slide the shaped vadai into the hot oil. Fry in batches, turning once or twice, until both sides are golden brown and crisp. Drain on a paper towel. Serve hot.
Notes
You can also finely chopped onions in the batter. I have done previously.
We are not big fan's of fennel and garlic in vadai so i have omitted them, you can add 1 garlic pod and ¼ teaspoon of fennel if you prefer.
Any leftover vadai, can be refrigerated and pulse it down to a crumble and make a brilliant paruppu usli the next day.