Heat 1tsp of olive oil in a frying pan and gently cook the onion until soft. Increase the heat and add the cumin seeds, garlic, chill, turmeric, ginger, coriander, and garam masala. Add the lamb and mix well. Cook the lamb until it is well browned and all the juices from the meat have evaporated. Tip the mixture into a large mixing bowl and leave to cool slightly
Preheat the oven to 190C
1 sheet of filo pastry makes 1 samosa. Carefully brush each sheet sparingly with olive oil before folding it in half lengthways. Brush the pastry with oil again.
With the pastry sheet stretched out in front of you, carefully put about 1 dessertspoon of mince at the bottom of the pastry sheet, closest to you. Carefully bring the bottom corner of the pastry up to form the beginning of a triangle over the mince. Continue to fold the pastry into triangles until the mince is completely enclosed in a triangular filo parcel.
Place the samosas on a greased baking tray and brush the top with a little more oil. Repeat until all the mince has been used up. Bake the samosas in the preheated oven for 25-30 minutes or until golden. Garnish with sprigs of fresh coriander and serve.