• In a small bowl, sprinkle the yeast over the lukewarm milk. Stir to combine and allow to sit until frothy, about 10 minutes.
• In the bowl of a stand mixer fitted with a dough hook or a large bowl, combine the flour, sugar, cardamom, and salt.
• Mix in the milk with the yeast, followed by the butter to form a dough. On a lightly floured surface, knead until smooth and soft. Place back in the bowl, cover with a towel or plastic, and allow to rise until doubled, about 1 hour.

To make the cinnamon filling:

• In a medium bowl, mix together the softened butter, sugar, and cinnamon until smooth.

To assemble:

• Preheat oven to 400˚F. Line two baking sheets with parchment or lightly grease.
• On a lightly floured surface, roll the risen dough into a rectangle about 24 inches long and 18 inches wide. Cover in an even layer with the cinnamon sugar filling. Roll up the dough, short end to short end to form a log. Pinch together the end to seal.
• Cut the log into rolls about 1 inch thick with a sharp knife. Arrange the rolls on the prepared baking sheets about 2 inches apart. Cover with a towel and allow to rise until puffed, about 30 minutes.
• Brush the tops of the rolls with the beaten egg. If using pearl sugar, sprinkle over the brushed rolls and bake in the preheated oven until golden, 12-14 minutes. Transfer the cooked rolls to wire racks to cool.
• If topping with a glaze: In a medium bowl, whisk the water into the powdered sugar to create a smooth glaze. If too thick, add a little more water. If too thin, add a little more powdered sugar. If desired, mix in a little cocoa powder to make the glaze chocolate. Drizzle the glaze over the cooled rolls, either a dollop in the center or around in a swirl.
• These Kanelsnegle are best the day they are baked.