Makes: 12 buns
Time: About 2½ hours, largely unattended
In Sweden, these S-shaped buns, called lussekatter, are eaten on Saint Lucia’s Day, the Festival of Lights celebrated in early December. The eggy dough bears resemblance to challah, with a generous pinch of saffron imparting a beautiful golden color and subtle, warm, and exotic flavor.
1. Heat the milk, butter, and saffron in a small saucepan over medium heat. When the butter melts, turn off the heat and let the mixture cool until lukewarm.
2. Put the flour, yeast, salt, and sugar in the bowl of a food processor and pulse to combine. Pulse in the whole egg and 2 of the yolks. With the machine running, pour in the milk mixture and process until the dough comes together into a slightly sticky ball. Turn the dough out into a lightly floured counter and knead until smooth and elastic, 5 or 6 minutes. Grease a large bowl with butter and put the dough in it. Cover with plastic wrap and let rise until nearly doubled in size, 1 to 1½ hours.
3. Press the dough to deflate and cut it into 12 pieces. Roll each one roughly into a log, cover with a kitchen towel, and let rest for 15 minutes. Line a baking sheet with parchment paper or grease with a little butter.
4. Working with one piece of dough at a time (and keeping the rest covered), roll it into a thin rope about 16 inches long. Tightly spiral either end of the rope around itself in opposite directions to make an S shape; if you’re using the raisins, stick one into the center of each spiral and then transfer to the prepared baking sheet. Repeat with the remaining dough. Cover the baking sheet with plastic wrap or a kitchen towel and let rise until puffy, about 45 minutes.
5. Heat the oven to 375°F. Whisk the remaining egg yolk together with 1 tablespoon water, brush the buns with the egg wash, and sprinkle with a little sugar. Bake for 15 to 20 minutes, until golden. Cool on racks before serving.