Preheat your oven to 375°F (190°C).
In a mixing bowl, combine the apples, granulated sugar, ground cinnamon, raisins, chopped walnuts, and lemon juice. Mix well.
Lay out one sheet of phyllo dough on a clean surface and brush with melted butter. Repeat with remaining sheets, stacking them on top of each other.
Spread the apple mixture evenly over the phyllo dough, leaving a 1-inch border around the edges.
Carefully roll up the dough, starting from one of the shorter sides, to form a log. Place the log seam-side down on a baking sheet.
Brush the top with more melted butter.
Bake for 35-40 minutes, or until golden brown and crispy.
Let cool slightly, then dust with powdered sugar before serving.