Heat 3 cups water in a pot. Turn off when the water turns slightly hot. Clean and cut the cauliflower florets to medium size. Add them to the hot water and leave for 3 mins.Discard the water and rinse them in fresh water. Drain them and set aside.
Add oil to a pan and heat it. When the oil turns hot, add cumin seeds. When the cumin seeds begin to splutter, add onions and . Saute till they turn golden. Keep stirring to fry them evenly.Add ginger garlic paste. Saute for 2 mins till the raw smell goes away.
Add potatoes and saute for 2 to 3 mins. Cover and cook on a low to medium heat until the potatoes are half cooked. Keep stirring in between. If needed sprinkle 2 tbsp water.
Add cauliflower and stir fry for another 2 mins.Add salt, turmeric and red chilli powder.Stir and mix to coat the spice powders well.
Cover and cook until the potatoes and cauliflower both turn soft and are fully cooked. If your veggies are too dry then you can sprinkle very little water and continue to cook covered.Keep stirring occasionally to prevent burning.Check if the potatoes are completely cooked. Sprinkle garam masala and coriander leaves. Mix well.
Cook covered for another 2 mins.Serve aloo gobi with rice or roti.