Preheat the oven to 400°F and line a baking sheet with parchment paper.
In a large saucepan combine the apples with water, butter, salt, cinnamon, lemon juice, sugar, and flour; stir to combine.
Cook over low-medium heat until butter sauce thickens, about 4 minutes. Remove from heat and cool completely.
Roll a sheet of puff pastry into a rectangle about 13x9-inch in size.
Add the apple filling in the center of the sheet.
Using a sharp knife or pizza wheel, cut strips along both sides of the pastry. You’ll have 10 strips.
Braid the pastry by crossing the strips diagonally over the filling overlapping each other.
Fold both ends at the top and bottom over the filling, this will prevent the filling from coming out during baking.
Bake until tops are golden and crispy, about 18-20 minutes. Once baked, remove from oven to cool before adding the glaze.
Meanwhile, prepare the glaze. Whisk together the powdered sugar with lemon juice and milk.
Once braid has cooled, drizzle glaze over the braid.