Add flour, salt and butter to a food processor and pulse to combine into pea sized pieces. Add sour cream and pulse to form a sticky dough. Cover and refrigerate for 8 hours.
Preheat the oven to 375°F. Line a baking sheet with parchment paper.
Make the filling by adding egg yolk in a medium bowl (reserve egg white for later to make an egg wash). Add cream cheese, brown sugar and cinnamon and beat with an electric mixer until smooth. Add 1 cup of chopped pecans and stir until combined. Set aside.
Divide chilled dough in half and on a lightly floured surface, roll each dough piece into 10x12 inch rectangles. Position the long side in front of you with the 10-inch sides on the sides.
Divide filling in half and spoon along the center of each rectangle. On the left and right sides of the filling, cut the sides into 8 horizontal strips. Starting at the top, fold each strip over the filling, pressing to seal the ends and tuck under. Using a large spatula, carefully place kringles on the prepared baking sheet.
In a small bowl, make an egg wash by beating the egg white and 1 tablespoon water together until smooth. Using a pastry brush, brush the wash evenly over the kringles.
Bake for 30-35 minutes or until golden brown. Let cool for 30 minutes.
While cooling, make the glaze by adding the sifted powdered sugar and half and half in a medium bowl. Drizzle over the kringles and sprinkle with remaining chopped pecans. Let set up before serving.