In a mixing bowl, combine all-purpose flour, salt, and sugar. Cut in the chilled, cubed unsalted butter until the mixture resembles coarse crumbs. Gradually stir in cold water until the dough comes together. Shape it into a disk, wrap in plastic, and refrigerate for 30 minutes to firm it up.

While the dough chills, prepare your filling. In a separate bowl, combine diced apples, brown sugar, cinnamon, lemon juice, and cornstarch. Mix well until apples are evenly coated. Set aside to meld flavors, and preheat the oven to 375°F (190°C).

Once chilled, roll the dough on a lightly floured surface into a large rectangle, about ¼-inch thick. Transfer onto a parchment-lined baking sheet.

Spoon the apple filling down the center of the rolled dough, leaving about 2 inches on both sides. Cut 1-inch diagonal slits along the edges of the dough. Fold strips over the apple filling, alternating sides to create a braid. Seal ends crisply.

Place in the preheated oven and bake for 25-30 minutes, or until golden brown. Remove and let cool on the baking sheet for about 10 minutes.

Whisk together powdered sugar, milk, and vanilla extract in a bowl until smooth. Adjust consistency if needed.

Drizzle the vanilla glaze over the cooled Apple Kringle. Allow glaze to set before slicing.