Saffron Bun Cake ("Saffransbutterkaka")

Saffron buns are a very important part of Swedish holidays; they’re most commonly baked for St. Lucia day on December 13th, but also for Christmas eve and day. Traditionally, they’re rolled into s-shaped buns and studded with raisins, but here I’ve filled them with a sugar-butter mixture, rolled the dough up like cinnamon buns, then baked the buns together in a springform pan.

• 1/2 tablespoon (½ gram) loosely packed saffron
• 1/2 cup (99 grams) granulated white sugar, divided
• 2 1/2 teaspoon (7 grams) instant yeast
• 1 cup (250 grams) whole milk, at room temperature
• 4 cup plus 2 ½ tablespoons (500 grams) bread flour
• 2 large eggs
• 7 tablespoon (100 grams) unsalted butter, softened
• 3/4 teaspoon Diamond kosher crystal salt

• 6 tablespoon (84 grams) unsalted butter, at room temperature
• 1/3 cup (66 grams) granulated white sugar
• 1 teaspoon vanilla extract
• a pinch of kosher salt

• 1 tablespoon melted butter
• 1/4 cup granulated sugar, or as much as needed