Preheat the oven to 375°F (190°C).
Prepare the apple filling by combining diced apples, cinnamon, brown sugar, and lemon juice in a bowl.
Roll out the croissant dough and cut it into triangles.
Place a spoonful of the apple mixture at the wide end of each triangle.
Roll the croissants towards the pointed end, forming a crescent shape.
Place the rolled croissants on a baking sheet lined with parchment paper.
Brush the tops of the croissants with the egg wash.
Bake in the preheated oven for 15-20 minutes or until golden brown.
Allow to cool slightly and dust with powdered sugar before serving.
