In a small bowl, soak the saffron threads in 1 tablespoon of warm water for about 10 minutes.
In a small saucepan, heat the milk until it is warm to the touch but not hot (about 110째F or 45째C).
In a large mixing bowl, combine the warm milk, granulated sugar, and active dry yeast. Stir gently and let it sit for about 5-10 minutes, or until it becomes frothy.
Add the soaked saffron (including the liquid), melted butter, egg, and sour cream to the yeast mixture. Stir to combine.
Gradually add the flour and salt, mixing until a soft dough forms. Start with 3 1/2 cups of flour and add more if needed to achieve a smooth, slightly sticky dough.
Turn the dough out onto a lightly floured surface and knead for about 5-7 minutes, or until the dough is smooth and elastic.
Place the dough in a lightly greased bowl, cover with a clean kitchen towel or plastic wrap, and let it rise in a warm place for about 1 to 1 1/2 hours, or until it has doubled in size.
Punch down the dough and divide it into 12 equal pieces.
Roll each piece into a long rope, about 12-14 inches in length.
Shape each rope into an "S" shape, tucking the ends into a spiral.
Place the shaped buns on a parchment-lined baking sheet.
Cover with a clean kitchen towel and let them rise for about 30-45 minutes, or until they are puffy.
Preheat your oven to 375째F (190째C).
Brush the risen buns with the beaten egg wash.
Place a raisin in the center of each spiral.
Bake the buns in the preheated oven for about 15-20 minutes, or until they are golden brown and sound hollow when tapped on the bottom.
Allow the buns to cool on a wire rack before serving.
Enjoy your meal!