In a deep pot over medium-high, heat the oil until, add in the cumin seeds, garlic, and cook until fragrant, about 30 seconds
Add the tomatoes, boiled potatoes, and stir in water just enough to submerge the, veggies
Add ground turmeric, ground coriander, ground cayenne/chili powder
Bring to a simmer, then cover and cook for 20 minutes, adjusting the heat to maintain a steady but gentle simmer.
Stir in the bell peppers, 1/4 cup water, and continue to simmer, uncovered, stirring occasionally, until the liquid is slightly reduced, about 5 minutes.
Mash a few cubes of potatoes, You do not need to mash them all the way - just a few pieces crumbled will give the curry a thicker consistency. Simmer for another 2 minutes
Adjust the consistency by adding some more water, if needed. If you do add water, make sure you simmer the curry for a few more minutes before turning the heat off
Taste and season with salt and pepper. Turn off the heat and transfer to a serving bowl and sprinkle with fresh cilantro.
Serve with rice or flat bread along with some lemon wedges, and thinly sliced onions.