Make the Middle Eastern topping by heating a large frying pan with a little olive oil. Sauté the onion with the spices (coriander, paprika, cinnamon and chilli flakes, if using) for 5 minutes. Add the tomato sauce and lamb, stirring to break it up with a fork and cook for 20 minutes or until cooked through. Add the fresh mint and season well. Pre-heat the oven to 220°C/425°F/Gas Mark 7. Empty contents of two sachets of the pizza mix into a bowl and stir in the warm water. Mix to a soft dough then knead well on a lightly floured surface for 5 minutes until smooth. Divide into 4 pieces. Roll out each piece into a circle approximately 20cm (8") diameter. Place on a baking sheet lined with nonstick baking paper. Leave to stand in a warm place for 10 minutes. Spread the lamb mixture over the pizza base to within ½cm (¼") of the edge. Top with the pinenuts and feta cheese. Bake for 10 minutes or until the base is golden and crispy. Enjoy with spoonfuls of tzatziki and garnish with sprigs of mint.