In a large mixing bowl, combine all-purpose flour, salt, and sugar. Cut in the chilled unsalted butter until the mixture resembles coarse crumbs. Gradually add cold water, mixing gently until a cohesive ball forms. Wrap in plastic wrap and refrigerate for at least 30 minutes.

Prepare the filling by mixing apples with brown sugar, cinnamon, lemon juice, and cornstarch in a medium bowl. Stir well until all apple pieces are coated, then set aside.

Preheat your oven to 375°F (190°C). Roll out the chilled dough into a rectangle, about 12x16 inches. Transfer to a parchment-lined baking sheet.

Spoon the apple filling down the center of the rolled dough, keeping it centered. Make 1-inch diagonal cuts along both sides of the filling. Fold flaps over to form a braid.

Bake for 25 to 30 minutes or until golden brown. Allow to cool for about 10 minutes before glazing.

Whisk together powdered sugar, milk, and vanilla extract until smooth. Adjust consistency if necessary.

Drizzle the glaze over the cooled Kringle and let it set for a few minutes before slicing.