Step 1: Make the Pastry
In a food processor, combine the flour, turmeric, and salt. Add the cold butter and lard, and pulse until the mixture resembles fine crumbs. Gradually add ice-cold water, a little at a time, pulsing until the dough just comes together. Turn the dough onto a clean surface, knead gently into a smooth ball, wrap in cling film, and chill for at least 1 hour.

Step 2: Prepare the Filling
Boil the diced potatoes in salted water for 10 minutes, or until just tender. Drain and set aside. Heat the oil in a non-stick frying pan over medium-high heat. Add the onions and a pinch of salt. Fry for 8–10 minutes, stirring, until soft and golden. Add the garlic, ginger, cumin seeds, chili powder, and turmeric. Cook for 1–2 minutes, until fragrant. Stir in the peas, followed by the parboiled potatoes. Add 3 tbsp of vegetable stock or water. Cook for 2–3 minutes, until slightly saucy but not dry. Remove from heat, season with lemon juice and more salt if needed, and allow to cool.

Step 3: Assemble the Pasties
Preheat the oven to 200°C (390°F). Line a baking sheet with parchment paper. Divide the pastry into 3–5 pieces, depending on your desired pasty size. Roll each piece into a round, using a plate as a guide for uniform circles. Spoon the potato filling onto one half of each pastry round, leaving a small border around the edge. Brush the edges with beaten egg, fold over to form a semi-circle, and crimp the edges to seal. Transfer to the prepared baking sheet. Brush with more egg wash and sprinkle with nigella seeds.

Step 4: Bake
Bake the pasties for 30 minutes, until golden and crisp. Allow to rest for at least 10 minutes before serving.

Step 5: Make the Chutney
In a mini chopper or blender, combine the coriander, ginger, chili, lemon juice, salt, sugar, and a splash of water. Blitz until smooth. Add the mint leaves and blend again, adding a little more water if needed for a smooth consistency.