Heat oil in a large Dutch oven over medium-high. Stir in cumin seeds; cook, stirring constantly, until lightly toasted and aromatic, about 1 minute. Stir in onion; cook, stirring occasionally, until beginning to caramelize, about 8 minutes. Stir in jalapeño, ginger, and garlic; cook, stirring constantly, until fragrant, about 1 minute. Stir in coriander, turmeric, and chile powder; cook, stirring constantly, until mixture is fragrant and spices are lightly toasted, about 30 seconds. Stir in tomatoes and salt until fully combined and mixture forms a paste.
Stir potatoes into mixture in Dutch oven; cook, stirring often, 5 minutes. Stir in 4 cups hot water, ensuring potatoes are fully covered. Bring to a boil over medium-high. Reduce heat to medium; cook, stirring occasionally, until potatoes are almost fork-tender, about 12 minutes. Stir in green peas and cilantro; cook, stirring occasionally, until peas are heated through and potatoes are fork-tender, about 2 minutes. Stir in ghee until melted and combined, about 1 minute. Serve hot.
