Cut cauliflower into bite-size florets. Heat some water in a pan till it starts to boil, add salt and blanch the cauliflower pieces for 2 minutes. Discard the water.
Heat cooking oil in a kadhai (wok). Add cumin seeds, and once they start to crackle and change the color slightly, add chopped garlic and chopped ginger. Fry for 1 minute on medium heat and then add and saute chopped onion until light golden.
Add chopped green chilies and chopped tomatoes. Fry till tomatoes are cooked and well combined with other ingredients.
Now add 2 teaspoons red chili powder, 1 teaspoon cumin powder, 1/4 teaspoon turmeric powder, 1 tablespoon tomato puree, and 2 tablespoon yogurt. Stir well and cook on low heat for 5 minutes or till oil starts to separate. If the spices stick to the bottom add a few drops of water.
Then add blanched cauliflowers pieces chopped potatoes, and salt. Stir well and cook covered on low flame till vegetables are just cooked (do not overcook). This will take about 10 minutes.
Finally, add 1/4 teaspoon garam masala powder, 2 teaspoon lemon juice, and chopped coriander leaves. Gently stir, taste, and adjust the seasoning. Cook for 2 minutes and turn off the flame.
Serve hot rotis, parathas, or buns.