Heat 3 tbsp of oil or ghee in a pot on medium low heat. Add sliced garlic and sauté for about 20 seconds.
Add coriander, cumin, fennel, mustard, nigella seeds to the pot. Sauté for about 1 minute until it all gets fragrant.
Add the turmeric powder.
Add the potatoes and stir to coat with the spice mixture. Cook on medium heat for about 6-8 minutes until potatoes are heated through and start to fry.
Season with salt and pepper to taste.
Now add tomatoes and green chillies and cover the pot. Turn the heat to medium low and let it cook for about 18-20 min.
Make sure to check it halfway through and stir to move the potatoes. If potatoes start sticking to the bottom, add a little splash of water, no more than a quarter cup. Make sure that the heat is low. Cover the pot and cook for the remainder of the time until potatoes are soft.
Once potatoes are soft, add dried fenugreek leaves and turn off the heat.
Garnish with cilantro and a squeeze of lemon. Serve with some plain yoghurt and bread (such as a naan or roti) for a complete meal. These potatoes also makes a great side dish.