Boil cauliflower florets in 3 cups water with 1/8 tsp turmeric and 1 tsp salt. Strain and set aside.
Dry roast cumin, pepper, fennel, cinnamon, and cloves until fragrant. Cool and grind to a fine powder.
Heat coconut oil. Add 1/4 tsp turmeric, garlic, curry leaves, and chili. Fry briefly.
Stir in ½ tbsp spice powder, then add onions and sauté until soft.
Mix curd and 1/8 tsp salt into onions. Add boiled cauliflower and ½ cup water. Cover and cook for 5 minutes.
Add tomatoes and remaining spice powder. Cook uncovered until moisture reduces.
Add soy sauce, mix well, and cook on high until dry.
Serve hot with onion slices.