Dough
3 cups all-purpose flour1 tablespoon sugar
1 envelope (2 1/4 teaspoons) instant or rapid-rise yeast
3/4 teaspoon salt
24 tablespoons unsalted butter, cut into 1/4-inch-thick slices and chilled
1 cup sour cream, chilled
1/4 cup orange juice (see note), chilled
3 tablespoons ice water
1 large egg yolk
Filling
1/2 cup granulated sugar
1/2 cup packed light brown sugar
1 tablespoon grated orange zest
2 teaspoons ground cinnamon
1 teaspoon vanilla extract
Combine flour, sugar, yeast, and salt in large zipper-lock bag. Add butter to bag, seal, and shake to coat. Press air out of bag and reseal. Roll over bag several times with rolling pin, shaking bag after each roll, until butter is pressed into large flakes. Transfer mixture to large bowl and stir in sour cream, orange juice, water, and egg yolk until combined.
Turn dough onto floured surface and knead briefly to form smooth, cohesive ball. Roll dough into 20 by 12-inch rectangle. Starting at short edge, roll dough into tight cylinder. Pat cylinder flat to 12 by 4-inch rectangle and transfer to parchment-lined rimmed baking sheet. Cover with plastic wrap and freeze for 15 minutes.
Line 12-cup muffin tin with foil liners and grease liners with cooking spray. Combine granulated sugar, brown sugar, orange zest, cinnamon, and vanilla in medium bowl. Remove dough from freezer and place on lightly floured surface. Roll dough into 20 by 12-inch rectangle and sprinkle evenly with filling, leaving ½-inch border around edges. Starting at long edge, roll dough into tight cylinder and pinch lightly to seal seam. Trim ½ inch dough from each end and discard. Cut cylinder into 12 pieces and transfer, cut side up, to prepared muffin cups. Cover loosely with plastic and refrigerate at least 4 hours or up to 24 hours.
Adjust oven rack to middle position and heat oven to 200 degrees. When oven reaches 200 degrees, turn it off. Remove buns from refrigerator and discard plastic. Place buns in turned-off oven until puffed and -doubled in size, 20 to 30 minutes. Remove buns from oven and heat oven to 425 degrees. Bake until buns begin to rise, about 5 minutes, then reduce oven temper-ature to 325 degrees. Bake until deep golden brown, 40 to 50 minutes. Cool buns in tin 5 minutes, then transfer to wire rack and discard liners. Serve warm.