In a large mixing bowl, combine the flour and salt. Add the oil and rub it into the flour until it resembles coarse crumbs.

Slowly add water, a little at a time, and knead until you get a stiff, smooth dough. Cover with a damp cloth and rest for 20 minutes.

Heat oil in a pan on medium heat, add cumin seeds and let them splutter.

Add ginger and green chilies, sauté for 30 seconds, then add green peas and cook for 2 minutes if fresh or 4 minutes if frozen.

Stir in the diced potatoes, turmeric, coriander, garam masala, chili powder, and salt. Cook for 4–5 minutes, mashing slightly but leaving some chunks.

Turn off heat, add lemon juice and cilantro. Let filling cool to room temperature.

Divide the rested dough into 6 equal balls, then roll each ball into a 6-inch circle and cut it in half to form two semi-circles.

Take one semi-circle, brush the straight edge with water, and form a cone shape. Fill the cone with 2–3 teaspoons of filling and pinch the open edges together to seal.

Repeat the filling and sealing steps for all dough balls.

Heat oil in a deep frying pan over medium heat. Fry 3–4 samosas at a time until golden brown and crisp, about 7–8 minutes per batch.

Remove the samosas with a slotted spoon and drain on paper towels.