Add all dough ingredients to a stand mixer bowl fitted with the dough hook and knead until smooth, about 5-7 minutes or so. Make sure the liquids are just warm, not hot. 95-100 degrees F (35-38 C) is best. If kneading by hand, it may take 8-10 minutes. Shape dough into a ball, cover and rest for 45 minutes.
Roll the dough out to about 55cmx30 cm or 21.5inx11.5 inches, roughly.Important: Make sure the bottom is not sticking to the surface, it will help later. Spread butter on two-thirds of the dough.
Mix the sugar, cinnamon and cardamom, if using. Sprinkle evenly over the butter.
Fold the bare side of dough over the middle, like turning a page or folding a letter. Then fold the other third over the middle also. You will now have a layered dough.
Cut the dough into ten equal strips. Then form your buns. See options in Notes.
Place on lined baking sheets about 5cm/2in apart and cover loosely, Let rise until puffy, 1 to 1.5 hours. Preheat the oven 20 minutes out to 420F or 215C.
Brush the buns with milk and sprinkle with pearl sugar.
You can also use granulated sugar, but it may caramelize and not have the exact same crunchy texture.
Bake the buns for about 15 minutes until golden brown. Meanwhile, prepare the sugar syrup, if using. Brush the buns with syrup while warm.