1. Prepare the Dough: In a large bowl, whisk together the all-purpose flour, granulated sugar, and salt. Cut in the cold, cubed butter using a pastry blender or two forks until the mixture resembles coarse crumbs. Stir in the sour cream until a soft dough forms. Gather the dough into a ball, wrap it in plastic wrap, and chill it in the refrigerator for at least 1 hour.

2. Create the Apple Filling: In a saucepan, combine the diced apples, brown sugar, cinnamon, nutmeg, and lemon juice. Cook the mixture over medium heat for 5-7 minutes, stirring occasionally, until the apples are tender and the filling has thickened slightly. Remove the filling from the heat and let it cool completely.

3. Assemble the Kringle: On a lightly floured surface, roll the chilled dough into a large rectangle. Spread the cooled apple filling down the center of the dough, leaving a bit of space on the edges. Fold the long sides of the dough over the filling, pinching the seams to seal. Carefully transfer the Kringle to a parchment-lined baking sheet, shaping it into an oval or horseshoe form.

4. Bake the Wisconsin Apple Kringle: Preheat your oven to 375°F. Bake the Kringle for 25-30 minutes, or until the crust is a beautiful golden brown. Allow the Kringle to cool slightly before drizzling the glaze over the top.

5. Make the Glaze: In a small bowl, whisk together the powdered sugar, milk, and vanilla extract until smooth and pourable. Drizzle the glaze over the warm Kringle, letting it drip down the sides for a lovely presentation.