heat 1.5 to 2 tbsp oil in a shallow frying pan or kadai. add 1/2 tsp cumin seeds and saute till they splutter and change color.
add 1/2 cup finely chopped onions.
saute till the onions turn translucent or a light brown.
add 1 tsp ginger-garlic paste. stir and saute till the raw aroma of ginger-garlic goes away.
then add 1/3 cup tightly packed chopped tomatoes and 1 green chili, chopped.
saute for 2 minutes.
then add 1/4 tsp turmeric powder, 1/4 tsp red chili powder, 1/2 tsp coriander powder and 1/2 tsp garam masala powder or pav bhaji masala.
stir and saute for two minutes more or till the tomatoes have softened.
add the chopped potatoes and shredded cabbage. stir and mix.
season with salt. stir again.
add 1/2 cup water. stir very well.
cover the pan tightly with its lid and simmer the veggies on a low flame.
do check at intervals if the water has dried or not. if all the water has evaporated, then add some water. i used 2/3 cup water. depending on the quality of veggies, the pan size etc, you can add from 1/2 to 2/3 cup water. do add more water if required.
once the potatoes are cooked well, switch off the flame. this is a dry dish. there should be no water in the dish. if there is any water left, then cook without the lid, till all the water evaporates.
garnish with coriander leaves and serve potato cabbage sabzi with chapatis or as a side dish.