Our tester’s family went crazy over these rich, buttery twists. Amazingly easy to make, they’re especially good right out of the oven, but they keep well, too.
In a mixing bowl, combine the flour and salt. Cut in the butter until the mixture resembles coarse crumbs. Add the sour cream and egg yolk and blend well. Shape the dough into a ball. Sprinkle lightly with flour. Wrap in plastic and chill for 2 hours or up to 3 days.
Preheat the oven to 350 degrees F. Lightly spray two baking sheets with nonstick cooking spray. Make the filling by combining the sugar, walnuts, and cinnamon in a small bowl.
Divide the dough into thirds. Roll each ball into a flat circle. Sprinkle a third of the filling on each circle. Cut into wedges, like a pie. Roll each wedge up from the wide end to the tip. Place on the baking sheets. Brush with egg white to glaze, if desired.
Bake for 25 to 30 minutes. Remove to wire racks to cool completely.