Heat a frying pan. Dry fry the coriander seeds until fragrant. Cool and pound using a mortar and pestle.
Heat the palm oil in the frying pan. Saute the onion with the coriander seeds, cumin and ginger powders until the onion bits are softened.
Add the potato cubes. Cook over high heat until the potato cubes are lightly browned in parts.
Off the heat, stir in the peas.
Season the filling with cayenne, pepper and salt. Cool before forming the samosas.