To a medium pot over high heat, add the oil. Once the oil is hot and shimmering, add the cumin and mustard seeds. As soon as they start to sizzle, add the shallots and cook, stirring frequently, just until translucent, about 3 minutes. Add the garlic and ginger and cook until fragrant, about 1 minute. Stir in the chiles and tomatoes and cook until simmering, 2–3 minutes. Season lightly with salt and stir in the turmeric, then add the peas and cook until the tomato juices have reduced slightly, 2–3 minutes more.
Stir in the paneer, turn the heat to low, and cover. Cook until the paneer is warmed through and softened, about 5 minutes. Remove from the heat and stir in the garam masala and cilantro. Serve with flatbread, sliced onion, and chutney if desired.
