Peel the apples, quarter them, and remove the cores and seeds. Cut the turkey breast into large chunks. Peel and quarter the onion. Place everything in a food processor and pulse to coarsely chop.
Heat the sunflower oil in a large skillet over medium heat. Add the chopped mixture and brown it, stirring occasionally. Stir in the whipping cream, cornflour, and white wine. Simmer for 5 to 8 minutes, then add the Smyrna raisins. Season with salt and pepper to taste. Mix well.
Preheat the oven to 210°C (thermostat 7). Butter a pie dish. Unroll one sheet of pastry into the dish and prick the base with a fork, allowing the edges to overhang. Fill with the turkey mixture. Top with the second sheet of pastry, slightly smaller than the dish. Moisten the edges of the top pastry and fold the overhanging bottom pastry over to seal, forming a neat pie crust.
Brush the top with the egg yolk beaten with a little water. Bake for about 30 minutes until golden and crisp. Serve warm with a lightly dressed green salad.
