Mix all the ingredients for the dough except water and rub thoroughly. Sprinkle in water as needed and make hard dough. Set aside to rest for 10 minutes. Divide the dough into balls about the size of a walnut.
Heat the olive oil and add cumin. When crackling, add ginger and salt. Add the rest of the ingredients excluding the chaat masala, fennel, garam masala and cashews. Cook and stir for 5 minutes.
Roll each portion of dough into a thin oval shape cut into 2 semi-circles. Apply water on the straight edge of the semi-circle. Fold the straight edge, bringing together the watered edges, seal the watered edges into a triangular pocket. Stuff the potato mixture and then seal the upper edges. Repeat with remaining ingredients.