Cinnamon Rolls (kanelbullar)

To make the dough, melt the butter in a saucepan over low heat. Add the milk, stir to combine, then let cool to 37°C.
Crumble the yeast into a large bowl. Add the milk mixture and stir until the yeast is dissolved. Stir in the sugar and salt.
Using a mortar and pestle, grind the cardamom, then stir into the liquid. Add the flour, little by little, and stir until the dough is smooth. Cover the bowl with a tea towel and set the dough aside for 40 minutes or until doubled in size.
To make the cinnamon butter, stir the butter, sugar and cinnamon in a bowl until a spreading consistency.
Transfer the dough from the bowl to a floured bench top and knock down dough. Using a rolling pin, roll out to a large 3 mm-thick rectangle. Spread the cinnamon butter evenly over the top. Carefully roll lengthwise to form a cylinder. Cut widthwise into 24 slices and place in paper cupcake cases on a baking tray. Cover with a tea towel and set aside to rise for 30 minutes.
Preheat the oven to 225°C. Lightly beat the egg and brush over the buns. Sprinkle with pearl sugar. Bake for 10 minutes or until golden.
Serve with cold milk.