How to make aloo parwal Curry परवल आलू की सब्जी़

Ingredients 10 to 12 parwal
1 1/2 cup diced potatoes
2/3 cup chopped onion
2/3 cup chopped tomato
1/4 tsp cumin seeds
1 tbsp coriander powder
1/2 tsp cummin powder
1/4 tsp chilli powder
1/4 tsp turmeric powder
1 tsp garlic ginger paste
1/2 tsp garam masala
3 tbsp mustard oil
1/2 tsp salt or salt to taste.