Heat oil in a deep non-stick pan and in cumin seeds. Once it starts to sizzle, add in ginger, garlic and onions. Fry till the onions become tender and start to lightly brown along the edges.
Stir in spices, salt and tomato paste to mix well.
Add in potatoes and stir-fry for 4-5 minutes till they begin to soften. If the potatoes and spices start to stick to the pan, then add in a splash of water to prevent it from burning.
Once the potatoes are partially cooked, add in the eggplant and tomatoes, and give it all a good mix to coat well with the spices. Cover and cook for another 4-5 minutes till the potatoes and eggplant are completely cooked through.
Garnish with fresh cilantro and serve warm.