Prepare 100 g fresh coriander. First, wash it thoroughly (fresh coriander is sometimes muddy!), then pat dry. Roughly chop. You can use tender (thin) stalks as well as the leaves for less food waste. Coriander stalks are packed with flavour!
Add 50 g chickpea flour to a large bowl. Slowly whisk in 400 ml water a little at a time (to avoid lumps). Then add sea salt (to taste), ⅛ teaspoon red chilli powder, ½ teaspoon coriander powder, ¼ teaspoon turmeric powder, and ¼ teaspoon ajwain seeds (crushed between your palms). Mix well.
Use a mortar and pestle to crush 3 green finger chillies and 5 cloves garlic to a coarse paste.
Add 1 tablespoon oil to a large kadai/deep frying pan over medium heat. Once the oil is hot, add ½ teaspoon cumin seeds and most of the 1 tablespoon white sesame seeds (reserve some for garnishing later). Cook until aromatic and just a touch coloured, then add the garlic-chilli paste. Sauté until aromatic.
Turn the heat to low and add the chickpea flour-spices mixture. Stir every now and then to prevent it sticking to the pan. Cook until the mixture thickens (you'll need to stir more continuously once this begins happening), which can take around 20 minutes.
Once the batter has thickened, pour it into a loaf tin (or similar sized tin) lined with parchment paper. Sprinkle the leftover sesame seeds on top. Move to the fridge to cool.
Once set and cooled, remove the parchment paper and set kothimbir vadi from the tin. Grease a knife with oil and cut into 18 evenly-sized squares.
Preheat 1 litre oil in a deep-fat fryer or deep kadai over medium-high heat. Once the oil comes to temperature (if it bubbles around a wooden spoon handle, it's ready!), carefully lower in a few pieces of kothimbir vadi. Fry until golden brown, then drain any excess oil on kitchen towel. Repeat with the remaining wadi.
Notes
You don't have to deep-fry kothimbir vadi. You can also pan-fry, shallow-fry, air-fry, or even bake the fritters!