Directions :
1. Line a baking sheet with parchment paper. Combine the pears, cinnamon,raisins, and sugar in a bowl, mix well,then set aside. Brushing the sheets of filo with a little melted butter as you work, layer 3 pastry sheets onto the baking sheet, then layer another 3 next to them, overlapping slightly.
2. Place another buttered layer of 3 sheets on top of them, with the long edges facing opposite, to form a cross.Repeat with another buttered layer of 3, overlapping slightly. The horizontal sheets should still show at the edges.Spoon the filling down the center,then fold in the edges. Top with a final layer of 3 buttered filo sheets, and brush butter over all. Double-wrap in plastic wrap and freeze.
3. To serve, defrost in the refrigerator overnight. Brush with more melted butter and bake in a preheated 375°F (190°C) oven for 30–40 minutes.
Variation : Use apples instead of pears.
Notes : Check the strudel halfway through cooking; if the filo has begun to brown too quickly, cover with foil.