Prepare all your ingredients, and have them readily available.
Add 2 tbsp. oil or ghee to a medium-sized pan or wok. Add the black mustard seeds and cumin seeds. Turn heat to medium-high and cook until the seeds begin to pop or splutter.
Once the seeds begin to pop and the oil is hot, add the chopped onion and green chilies. Cook, stirring occasionally, for a few minutes or until the onions become translucent.
Add garam masala, turmeric powder and chili powder. Stir well and cook for about a minute before adding in the cooked, diced potatoes.
Cook the potatoes for a couple minutes or until they begin to turn light-golden brown.
Add 1 tsp. lemon juice and the chopped roma tomato. Stir everything to combine. Cook this masala mixture for a couple minutes, until you notice the tomato begins to turn soft.
Add the diced bread and quickly stir everything around, ensuring each piece of bread is coated with the masala mixture.
Stirring constantly, cook the upma until the bread becomes crispy and lightly toasted. This may take anywhere from 2 to 5 minutes.
Add the chopped cilantro leaves and stir to combine. Season with salt and pepper, to taste.
Serve with eggs, lime wedges and extra cilantro. Enjoy!