If the saffron is not already grinded. Grind the saffron threads in a mortal.
Crumble the fresh yeast into a big mixing bowl.
In a separate medium sized bowl, melt the butter.
Add saffron to the melted butter and stir.
Add milk to the melted butter and stir.
Microwave the liquid until it reached room temperature (37 C) and stir.
Pour the liquid into the big mixing bowl and stir until the yeast has dissolved.
Add sugar and salt and stir.
Add flour and knead the dough by machine for about 5 min or by hand for 10 min. I recommend using a machine since the dough will be quite sticky.
Cover the bowl and let it rest for 35 min.
Transfer the dough onto a lightly floured surface and make 15 lussekatter.
Place the lussekatter on a baking sheet, cover and let them rest for 35 min.
Meanwhile, soak the raisins in hot water.
Preheat the oven to 200 C.
Brush the lussekatter with a whisked egg and push in the raisins.
Bake the lussekatter in the middle of the oven for about 8-9 min.
Let cool for a few min and enjoy!