Begin by chopping the bread slices into bite-sized cubes. If the crust is too tough, trim it off and set it aside — you can blend those pieces into breadcrumbs for later use.
Finely dice the onions, tomatoes, green chili, and ginger. Roughly chop the curry leaves and coriander leaves, then set all the prepped ingredients aside.
In a heavy-bottomed skillet or pan, heat the oil over medium heat. Add the mustard seeds and allow them to crackle and pop, releasing their aroma. Follow with the cumin seeds and sauté until they deepen in color and become fragrant.
Add the chopped onions and cook them over low to medium heat until they turn translucent. Stir in the green chilies, ginger, and chopped curry leaves. Continue to sauté for another 10 to 12 seconds, until the raw scent of the ginger dissipates.
Toss in the chopped tomatoes, followed by turmeric powder, red chili powder, and a pinch of asafoetida, if using. Stir everything together thoroughly and season with salt. Let this mixture cook down until the tomatoes are soft and fully cooked — you should see a bit of oil releasing from the sides of the mixture. Make sure there’s no extra moisture left; the base should be mostly dry to prevent the bread from turning soggy.
Add the bread cubes into the pan and fold them gently into the mixture, coating them evenly. Continue to sauté on low to medium heat for 4 to 5 minutes, allowing the bread to slightly crisp on the edges while remaining soft in the center.
Finally, sprinkle in the chopped coriander leaves and give the dish a quick stir. Alternatively, you can use the cilantro as a garnish just before serving.
Serve the bread upma hot, either for breakfast or as a quick savory snack. A squeeze of fresh lemon juice over the top just before serving adds a delightful tang.