First, make the harissa yoghurt sauce. Mix the yoghurt and the milk together to make a thin sauce. Stir in the mint and cilantro and season to taste with salt and pepper. Lightly stir in the harissa paste, and set the sauce aside.
Preheat oven to 200°C (390°F).
Heat a small skillet over medium heat and dry-roast the coriander and cumin seeds, taking care not to burn them. Grind them coarsely with a mortar and pestle or an electric spice grinder, then transfer to a small bowl. Mix in the paprika, cinnamon, 1/2 teaspoon salt and 4 tablespoons of the olive oil.
Place the winter squash in a roasting tin, then pour over the spiced oil and toss well to ensure each piece of squash is coated with the oil. Roast for 20 minutes in the pre-heated oven, then set aside.
Meanwhile, heat 2 tablespoons of the olive oil in a skillet, then add the shallots and cook, stirring, until they start to brown. Stir in the chopped ginger and 3 1/2 oz each of the almonds and pistachios, reserving the remainder. When the nuts are golden brown, add the craisins, 2 tablespoons of honey, and the spinach. When the spinach wilts, remove the skillet from the heat and stir in the roasted winter squash. Set aside.
Process the chickpeas, garlic, cumin, the remaining oil, lemon juice, 2 tablespoons of water, and salt and pepper to taste, in a processor or with a stick blender. Stir in the chopped cilantro.
Melt the butter in a small pan. Place a loose-bottomed 11 inch quiche tin on a baking sheet and brush with some butter. Keeping the phyllo covered with a damp cloth so it doesn’t dry out, lay one sheet over half of the tin so that it hangs over the edge by about 4 inches. Lay another sheet on the other side, so it overlaps the first in the centre and hangs over the opposite edge. Brush with butter. Lay two more phyllo sheets in the opposite direction in the same way and brush with more butter. Build up two more layers in this way, so there is a total of eight sheets of phyllo.
Pile half the squash mixture in the centre of the pastry. Cover with the chickpea mixture, then top with the rest of the squash mixture.
One at a time, bring the edge of each phyllo sheet up to the centre to cover the filling, creating voluptuous folds as you go. Brush carefully with more butter.
Bake the pie for 30-35 minutes, until crisp and golden. Cover loosely with foil if browning, too quickly, near the end of cooking time.
Just before the pie is ready, reheat any remaining butter, in the pan, add the remainder of the nuts and saute until golden. Spoon in the remainder of the honey and, when it melts, remove from heat and pour over the pie.
Serve with harissa yoghurt sauce and lemon wedges, and a large tossed green salad.