Preheat your oven to 400°F. Line two baking sheets with parchment paper and set aside.

In a medium saucepan over medium heat, combine the diced apples, brown sugar, cinnamon, nutmeg, ginger, butter, flour, and lemon juice. Cook, stirring occasionally, until the apples are tender, about 7 minutes. Remove from heat, stir in vanilla extract, and let cool.

Lightly flour a work surface and unfold one sheet of puff pastry. Cut it into 6 equal rectangles and transfer them to the prepared baking sheets.

In a small bowl, whisk the egg with 1 tablespoon of water. Brush a thin layer of egg wash around the edges of each rectangle. Spoon about 1 tablespoon of the cooled apple filling into the center of each rectangle.

Roll out the second sheet of puff pastry on the floured surface and cut into 6 equal rectangles. Place one rectangle over each filled bottom rectangle. Gently press the edges together with your fingers, then crimp all around with a fork to seal. Poke the tops a few times with the fork to allow steam to escape. Brush the tops evenly with the remaining egg wash.

Bake the strudels until they are puffed and golden brown, 18 to 20 minutes. Let them cool slightly on the baking sheets.

While the strudels cool, make the glaze: In a small bowl, whisk together the powdered sugar, maple syrup, milk, vanilla extract, and salt until smooth. The glaze will be thick. Microwave for 15 seconds to warm and thin it slightly, then drizzle over the warm strudels. Allow the glaze to set before serving.