1.
Pastry: Sift the flour into a bowl and rub in half the butter. Add the water and mix to a soft dough.
2.
On a lightly floured surface, roll the dough into a rectangle about 5mm thick. Dot half the remaining butter pieces over the top two-thirds of the rectangle, then fold the bottom third up and over the centre third. Then bring the top third down so that it covers the bottom third. Press the edges together with the rolling pin.
3.
Give the dough a quarter turn to the left so that the side joins are to the bottom and top. Roll out again into a rectangle 5 mm (1/4 in) thick. Dot the vegetable fat over the top two-thirds of pastry; fold and turn as before. Repeat, using remaining butter. Wrap the dough in plastic wrap and chill for 30 minutes.
4.
Filling: Place the apples, dates, prunes, orange juice, sugar and cinnamon in a pan. Cook gently, covered, for 8 minutes. Remove from heat; cool.
5.
Preheat oven to 220 degrees C. Cut the dough in half and return one half to the refrigerator. Roll out one piece to make a 35×25cm rectangle. Cut in half lengthwise and into 3 crosswise to make 6 pieces, each 12cm square.
6.
Spoon half the filling onto the centre of the squares, dividing it up equally. Brush the edges with a little whisked egg, then fold each square in half diagonally to enclose the filling and to form a triangle. Press the edges together well to seal and crimp them with the tines of a fork.
7.
Put the turnovers on a baking sheet and refrigerate while making 6 more in the same way with remaining dough and filling.
8.
Brush the turnovers with the remaining whisked egg; sprinkle with sugar. Bake for 20–25 minutes or until well risen, crisp and golden. Cool briefly on wire racks.