• With a mortar, reduce the saffron to powder.
• Place in a saucepan the milk and gently heat it until it will be lukewarm. Add into the pan the yeast or sourdough, the saffron, the cardamom and the sugar. Stir until the sugar won’t be dissolved.
• Break an egg into a small bowl and beat it with a fork. Stir half of the egg into the milk batter. Keep what’s left of the egg, we’ll need it later to brush the rolls.
• Place the flour in a stand mixer bowl and add the salt. Turn your stand mixer on and add the milk batter little by little.
• Add the butter cubes, one at a time, and work until completely dissolved.The dough will be a little sticky to the touch, so don’t be tempted to add more flour – this will make the rolls dry.
• Cover the bowl with a damp, clean kitchen towel and leave the dough to rise for 12 hours.

Shaping

• Line two baking sheets with baking paper.
• On a floured surface, roll out the dough into a 45 x 30 cm (19.6 by 12.5 inch) rectangle.
  
• Spread the butter evenly over the dough, almost all the way out to the edges.
  
• Sprinkle the cinnamon on top of the whole dough.
  
• Roll the dough upon itself.
  
• Use a knife or a bench scraper, cut triangles approximately 6cm wide.
  
• Turn the triangles with the pointy end upward and flatten it using one finger. Let the rolls rise for 30 minutes, meanwhile the oven preheats.
  

Baking

• Preheat the oven to 225°C/437°F.
• Whisk together the egg and milk or water in a small bowl. Brush the rolls with the egg mixture.
  
• Bake one sheet at a time, for 12 minutes or until the rolls are golden brown. Let the rolls cool down.
  

Glazing

• Stir all the ingredients together. Top the rolls with the glaze.