For the strudel
Toss the apples with the raisins, walnuts, sugar and cinnamon. Place one sheet of phyllo dough on the working surface with the long side facing towards you. Brush the dough with ¼ of the butter and the sprinkle ¼ of the crumbled streusel or biscuits. Top with a second sheet of phyllo, brush with the same amount of butter and sprinkle the same amount of crumbled streusel or biscuits. Place ½ of the apple filling in a straight line along the long side of the phyllo leaving about 2-3 cm space on each side. Fold the 2 sides of the phyllo over the edges of the filling and the roll tightly so that a nice log is formed. Repeat the same procedure with the rest of the ingredients to form one more log. Brush the tops of the logs with melted butter. Vent the tops of the strudels by making 3 - 3cm incisions on a diagonal dividing the log into 4 pieces. Bake in a preheated oven at 180⁰C until light golden brown, about 25 minutes. Let cool down slightly before cutting. It can be served warm or at room temperature.