½ gram saffron
1 cup whole milk
1 tablespoon active dry yeast
⅓ cup sugar, plus a pinch for proofing the yeast
3½ cups flour
½ cup sour cream
1 teaspoon table salt
4 tablespoons butter, softened
1 tablespoon water
36 dried, sweetened cranberries
Swedish pearl sugar (optional, but so good – available at King Arthur Flour or Sur La Table) for sprinkling
On a small plate, grind the saffron with the back of a spoon until it is powdered. If you have a mortar and pestle, that will work wonderfully.
In a small saucepan over medium-low heat, heat the milk until just beginning to simmer. Remove the pan from the heat, add the saffron, and stir. Allow the mixture to cool to the temperature of a warm bath. When the milk is warm but not hot, add the yeast and a pinch of the sugar. Allow the mixture to sit until it is bubbling and has grown in volume, about 5 minutes
While the yeast mixture is proofing, in a large bowl with a wooden spoon or in the bowl of a stand mixer fitted with the dough hook attachment, combine the sugar, flour, sour cream, and salt.
Add the yeast mixture, and knead until the dough is nice and smooth, and pulls away from the sides of the bowl.
Add the butter, 1 tablespoon at a time, and continue kneading the dough until it again pulls away from the sides of the bowl. It might seem like this is never going to happen, but all of a sudden, you’ll have a nice, smooth ball of dough.
Put the dough in a lightly oiled bowl, cover with plastic wrap, and allow it to rise until doubled in size.
Punch down the risen dough, knead it briefly on a lightly floured counter, and divide the dough into eighteen equal portions.
Roll each piece of dough into a long, skinny strip, about 12 inches long. Roll the left end of the dough up and clockwise until it reaches the middle, then roll the right end down and clockwise until it reaches the middle. Your dough should now look like a very tightly rolled S.
Place the Ss on a parchment-lined baking sheet, cover with plastic wrap, and allow them to rise for 30 minutes.
Preheat the oven to 400 degrees F. While the buns are rising, in a small bowl, whisk together the egg and water. Just before baking, lightly brush the tops and sides of each lucia bun with the egg wash, place a cranberry at the center of each swirl, and sprinkle the tops with pearl sugar.
Bake the lucia buns for 8 minutes, or until they are puffed and golden. Remove the baking sheet from the oven and allow the buns to cool. Store leftovers in an airtight container.