In a big baking bowl, crumble the yeast.
In a sauce pan melt the butter.
Pour he milk in the melted butter, and stir until it becomes luke warm.
Pour the liquid over the yeast and stir very gently until the yeast is resolved.
Add the sugar, 1 egg, salt, cardamom and almost all of the flour. Work it all with your hands until you get a dough. It should not be sticking on the bowl.
Cover the bowl with plastic foil and let it rest for 1 hour.
Take away the plastic foil and ads the rest of the flour.
Divide the dough in 6 pieces and form balls.
Place the buns on a baking paper, cover with a baking towel. Let them rest for 1 hour.
Preheat the oven at 220 degrees Celsius.
Stir 1 egg and brush the buns with it.
Place the in the middle of the oven for 10 minutes.
Take the buns out and let them cool down.
Whip the cream together with half of the nutella and all of the vanilla sugar to a fluffy foam.
Cut away the top of each bun.
Dived half of the nutella evenly on the buns.
Spread evenly the whip cream on the nutella with the help of a piping bag.
Place the top back on each semla. Sprinkle son icing sugar on top before serving