Heat the oil in a pan over a low heat, add the onions and spices and fry until the onions are soft and translucent. Add the carrot and parsnip and
Add the walnuts, Hot Spice Paste (or harissa paste) and garlic and mix well. Transfer the onion mixture to a bowl and use your hands to mix it with the mince, parsley, lemon zest and juice, salt and breadcrumbs. Add the egg and mix it into the mixture well.
Place the two sheets of pre-rolled puff pastry on a baking tray and cut both in half lengthways down the middle.
Divide the mince mixture into 4 portions, then make a long sausage along the middle of each piece of pastry. Brush the edges of the pastry with a little of the beaten egg and fold the pastry over the mince, pressing together firmly to seal.
Turn the rolls over so they are seam-side down on the baking tray and cut each of them into 4 pieces, making 16 in total.
Brush again with the beaten egg, then sprinkle with the sesame and poppy seeds.