Prepare all your veggies. Cut half a cauliflower into florets. Cut one large carrot diagonally to form thin slices. Quarter your potatoes so they are about 1-inch.
Add 2 tbsp oil to a large saucepan over medium heat. Add 5 cloves, 1 cinnamon stick, 1/2 tsp mustard seeds, and 1/2 tsp fenugreek seeds. When it starts to crackle, add the 12 curry leaves and 2 red chilis. Continue to fry the whole spices in the oil for 2 minutes.
Add the chopped onion and grated ginger. Cook for 2 minutes before adding 1/2 tsp turmeric and 1 tsp kashmiri lal (sub 3/4 tsp red chili powder). Cook with the ground spices for 1 minute, making sure they don't stick to the pan.
Add 1 cup of tomato paste, 1 tbsp tamarind paste, and salt. Cook for 5-7 minutes, allowing the tomato juices to mostly evaporate.
Add potatoes and 1/2 cup water. Cook for 5 minutes before adding carrot and cauliflower. Cook carrot and cauliflower for 3-4 minutes before adding another 1.5 cups of water.
Bring to boil, reduce to low, cover, and simmer for 15 minutes or until veggies are soft and cooked. If the potatoes are not fully cooked at this point, that's ok. They should be soft, but they can finish cooking after you take them off the heat by simply keeping the pot covered.
Finally, add chickpeas and coconut milk. Cook for 4-5 minutes. Remove pan from heat and stir in spinach. The spinach will wilt in the warmth of the curry. Add salt and lemon juice to taste if needed.
I recommend serving with rice. As with most curries, the flavor gets better with time, so definitely save some for the next day!