In a large bowl, mix together the potatoes, peas, cumin, amchoor, chillies, onion, coriander, mint and lemon juice. Season with salt and pepper to taste and set aside.
Fold each sheet of filo pastry in half lengthways. Put a large spoonful of the potato mixture at one end and then fold the corner of the pastry over the mixture, covering it in a triangular shape. Continue folding over the triangle of pastry along the length of the pastry strip to make a neat triangular samosa.
Place the samosas on a greased baking sheet, brush with melted butter and bake in a preheated oven at 200°C (400°F), Gas Mark 6 for 15–20 minutes or until golden. These crisp savouries can be made in advance and frozen. They can then be cooked straight from the freezer.
Serve with Mango, Apple & Mint Chutney (see