Add ground coriander, turmeric powder, curry powder, and red chili powder. Stir well to coat the onions with the spices.
Pour in the diced tomatoes with their juices. Cook for 3-4 minutes until the tomatoes break down and the mixture becomes fragrant.
Stir in the coconut milk and bring the mixture to a gentle simmer. Let it cook for another 5 minutes, allowing the flavors to meld.
Add the cauliflower florets to the curry. Mix well. Cover the pot and let the curry simmer for 15-20 minutes or until the cauliflower is tender. Season with salt and pepper to taste.
Stir in garam masala just before serving. Serve with rice or with naan bread.
