Heat oil in a deep pan and add in the cumin seeds and garlic cloves. As soon as they begin to sizzle get become fragrant, add in the onions, and fry for 2-3 minutes on medium-high heat until it starts to soften and brown along the edges.
Mix in the spices, salt and tomato paste, and fry for a few seconds to blend well.
Add in chopped tomatoes, mix well and cook covered for a couple of minutes until the tomatoes soften and start to pulp.
Add in the potatoes and about a cup or so of water - you can add more water if you prefer your curry to have a thinner consistency. Give it a quick stir, lower the heat to medium and let it come to a boil.
Garnish with freshly chopped coriander leaves and serve immediately.
