Heat ½ tablespoon oil in a pan and add cauliflower florets to it. Sauté them on medium heat for 2 minutes and add potato slices. Continue to sauté them over medium heat for 5-7 minutes. Veggies will get a few brown spots on them by this time. Take them out in a bowl and set aside.
Heat 1.5 tablespoon of oil in the same pan over medium heat. Add cumin seeds to oil and allow them to crackle.
Now add finely chopped ginger and garlic. Sauté for about a minute till their aroma gets absorbed in the oil.
Next add chopped onions in the pan and sauté till they turn golden. It should take about 5 minutes You can also add a whole green chili at this point of time. It is optional, but adds to the flavor!
Add chopped tomatoes, cook for a minute. then add all the spices (turmeric, coriander, dry mango powder, garam masala and red chili powder) and a little salt. Cover and cook till the masala gets soft and comes together.
When tomatoes and spices get cooked, add semi-cooked potatoes and cauliflower florets in the pan. Mix them well in the tomato-spice mixture. Now cover the pan with a lid to prevent steam and moisture. Let them cook on low to medium flame.
Stir from time to time and splash little water to prevent sticking to the bottom of the pan (if needed). After 5 minutes, add the remaining salt, give it all a stir and cover again. Cooking the veggies should take about 10-12 minutes.
Top with cilantro, squeeze some lemon on it, stir and server hot!