Nazook (Sweet Persian Pastry)

1. Combine 1 cup sour cream, 2 teaspoons sugar, and yeast in a bowl; let stand for 5 minutes. Stir in egg, vinegar, and oil.

2. Add 3 cups flour to a large bowl. Cut in 1/2 cup butter with 2 knives or pastry blender until mixture resembles coarse crumbs. Stir in sour cream mixture until dough comes together.

3. Turn dough out onto a floured surface; knead until smooth but still slightly tacky, about 10 minutes. Cut dough into 4 pieces; wrap each in plastic wrap. Refrigerate until firm, 2 hours or up to overnight.

4. Preheat the oven to 350 degrees F (175 degrees C).

5. Combine 2 1/2 cups sugar, 1 pound melted butter, and vanilla extract in a very large bowl; stir in 4 cups flour. Beat egg whites into filling mixture.

6. Roll 1 piece dough on a lightly floured work surface into an 8x12-inch rectangle. Crumble 1/4 filling mixture on top, leaving a 1/2-inch border on long sides. Cover filling with plastic wrap; flatten with a rolling pin. Roll dough into a tight roll, starting with one of the long sides.

7. Cut roll into 2-inch pieces at a slight angle. Arrange pieces on a rimmed baking sheet. Push tops down gently to flatten slightly. Repeat with remaining 3 dough pieces and filling.

8. Whisk egg yolks and yogurt together; brush over dough pieces.

9. Bake in the preheated oven until golden brown, 20 to 30 minutes. Cool before serving, about 15 minutes.

Cook's Notes:

I have kept these in the refrigerator for up to 1 week, warming them slightly in the microwave before eating. I'm sure they would also freeze just fine. I have also assembled just 1 or 2 pieces of dough at a time, leaving the rest of the dough and filling in the fridge for a few days, until I was ready to bake more.

Substitute sour cream for the yogurt in the glaze if desired.