In a small bowl, whisk the active dry yeast and 1 tablespoon of granulated sugar into the warm milk. Let it sit for about 5 to 10 minutes until the mixture becomes frothy and bubbly.

In a large mixing bowl, combine the flour and salt, then stir in the yeast mixture, softened butter, and egg. Knead the dough on a lightly floured surface for about 8 minutes until it is smooth, soft, and elastic.

Place the dough in a greased bowl, cover it with a damp cloth, and let it rise in a warm spot for about 45 minutes to 1 hour until it doubles in size.

While the dough rises, prepare the coating by mixing the dark brown sugar, ground cinnamon, and freshly grated orange zest in a shallow dish. Ensure the orange zest is thoroughly distributed through the sugar to release its fragrant citrus oils.

Divide the risen dough into 8 equal portions and roll each piece into a log about 10 inches (25 cm) long. Let these dough logs rest for 5 minutes to relax the gluten, making them easier to shape.

Roll each log generously through the orange-cinnamon sugar mixture until completely coated. Wind each sugar-coated log into a tight spiral coil, tucking the outer end firmly underneath so it stays secure during baking.

Place the coiled bolussen onto a baking sheet lined with parchment paper, leaving space between them, and let rise for another 15 minutes. Bake in a preheated oven at 400°F (200°C) for 12 to 15 minutes until the sugar melts into a bubbly, sticky caramel.

Immediately invert the hot pastries onto a clean piece of parchment paper to prevent them from sticking to the baking sheet as they cool. Let them cool slightly, then serve warm when the caramelized glaze is at its gooey best.