Pre-heat the oven to 150 C. Rinse the quinoa and cook 15 minutes over a low heat and covered in lightly salted water, drain and set aside in a bowl.
In a large roasting tin, lay a large sheet of foil, place the lamb in the centre, top with the garlic, herbs and the butter and seal tightly. Place in the oven and roast for 2 ½ hours, leave to cool then shred the lamb from the bone and mix with the quinoa. Turn the oven to 210 C.
Make the samosas by pulling strips of filo pastry off the stack and brushing them with butter. Place a tablespoon of the lamb mixture at one end of the strip and fold the strips into triangles. Brush with butter and place on a wire rack in the oven until golden brown.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.