For the filling, mix almond paste, pear sauce, warm milk and icing sugar. The mixture should be smooth and be easily spreadable.
Roll out the puff pastry on a baking sheet, lengthwise. Spread the almond paste mixture down the middle of the dough, leaving a 3 cm border free on each side. Fold the pastry lengthwise and seal the edges of pastry by pinching extremities together.
Preheat oven on 400F.
Whisk egg and brush onto top of pastry
Bake for 30-40 min. If Strudel turns golden too quickly, cover with aluminum.
Decorate with icing sugar