Boil the potato halves in salted water until just fork-tender but still slightly firm inside. Drain and let cool. Roughly mash into uneven chunks.

In a blender, combine the 1 small bunch of fresh cilantro, ginger, green chilies, and black pepper with a splash of water. Blend into a smooth green paste and set aside.

In a separate bowl, mix the Kashmiri chili powder and regular chili powder with 3 tablespoons of water to make a red chili paste.

Heat mustard oil in a wide pan over medium heat until it begins to shimmer. Add the cumin seeds, black cumin seeds, mustard seeds, and fennel seeds. Let them crackle for a few seconds. Add the green herb paste and sauté for 3 to 5 minutes, until the oil begins to separate.

Stir in the dried red chilies, turmeric, and salt. Add the red chili paste and cook for another 3 to 4 minutes, stirring until the oil rises to the top.

Pour in the hot water and bring to a boil.

Add the semi-mashed potatoes, stir gently, and reduce the heat to low. Lightly toast the fenugreek leaves in a dry pan, then crush them between your palms and sprinkle over the curry. Stir in the boiled peas and simmer for 5 to 7 minutes, until the gravy thickens slightly.

Garnish with chopped fresh cilantro and serve hot.