Melt the butter in a sauce pan, and pour in the milk in the melted butter. Heat up the mixture to finger temperature 37 degree Celsius.
Crumble the yeast in a bowl, add a small amount of the butter mixture, stir until the yeast is dissolved, and then add the rest of the butter mixture.
Pour the salt, sugar, cardamom, and 2/3 of the fluffed flour in the mixture.
Work the dough until it become shiny and smooth, and then add some more. The dough is ready when it does not stick to the bowl anymore. Save about 132 gram of the flour till it is time to bake the dough.
Cover the bowl with a towel, and put the bowl in room temperature where it´s not windy. A perfect place is in the oven with no heat at all.
Let the dough double in size, for around 1 hour.
Now it is time to do the filling. Put the butter in a bowl and smash it with a fork. Add the sugar and cinnamon, and work it all together with a fork to an even mixture.
Take the dough out from the bowl and place it on the table, and work the bubbles out of the dough. Add some more flour.
Bake the dough on the table to rectangles, make sure to not make the dough to thin.
Spread the filling on the dough.
Roll the dough into rolls.
Cut the rolls in 2-3 cm thick pieces. And put them in Swedish bun paper / cupcake paper.
Let the buns rest under a towel for 30 minutes.
Start the oven to warm air on 225 degrees Celsius
Stir the egg with a fork, and brush it on the buns. Spread chopped almonds or the decoration sugar on the buns.
Put the buns in the middle of the oven for 8-10 minutes.
Take out the buns and let them cool down under a towel in room temperature.