01 - Set a large skillet over medium heat and pour in the vegetable oil, allowing it to shimmer before adding any ingredients.
02 - Add the chopped onion to the hot oil and cook for 3 to 4 minutes, stirring frequently, until the pieces turn translucent and soften.
03 - Stir in the minced garlic, chopped chiles, and tomatoes if using. Continue cooking for 2 to 3 minutes until the mixture becomes highly fragrant and the chiles soften.
04 - Add the diced potatoes to the skillet along with the ground cumin, smoked paprika if using, salt, and pepper. Toss everything together so the potato pieces are evenly coated in the spice mixture.
05 - Pour in the vegetable broth or water, cover the skillet with a lid, and cook for 20 to 25 minutes. Stir occasionally to prevent sticking, until the potatoes are fork-tender and most of the liquid has been absorbed.
06 - Remove the lid and taste the dish. Add more salt or pepper as needed, allowing any remaining liquid to cook off for a minute or two.
07 - Transfer to a serving dish and scatter freshly chopped cilantro over the top. Serve warm as a hearty side or a satisfying main.