In a mixing bowl, combine flour, salt, and sugar. Cut in the cold butter until the mixture resembles coarse crumbs.

Gradually add cold water, mixing until the dough comes together. Wrap in plastic wrap and refrigerate for 30 minutes.

In a separate bowl, mix diced apples, cinnamon, brown sugar, lemon juice, and cornstarch until well combined.

Preheat the oven to 375°F (190°C). Roll out the chilled dough on a floured surface into a rectangle.

Spread the apple filling down the center of the dough, leaving space on the edges. Fold the edges over the filling and pinch to seal.

Transfer to a baking sheet lined with parchment paper. Bake for 30 minutes or until golden brown.

In a small bowl, whisk together powdered sugar, milk, and vanilla until smooth. Drizzle over the warm kringle.