Pullataikina - Finnish bun dough

This is the basis for many types of Finnish pulla's, including the very simple one with no filling.
I think it deserves its own post :), not to mention how much easier it will be to just link it next time when I make some Dallaspulla..

Ingredients (makes ~16 buns)
500 ml milk (2 cups)
2 tsp (2 bags) dry yeast
1 egg
200 ml sugar (a bit less than 2 cups)
150 g butter (a bit less then 1 1/2 stick)
1 tbsp minced cardamom seed
1 tsp salt
~900-1000 g (~2-2.2 lb) all purpose (bread) flour,  1300-1500 ml (5-6 cups) depending on the type of flour used (it tends to be more towards the 1 kg with most bread flours)
1 tsp vanilla sugar or the seeds of 1 vanilla bean (optional)

Brushing
1 egg
1-2 tbsp water

Warm up 1 dl milk to ~hand warm, let the yeast to trot for couple of minutes.
Add to the rest of the milk, whisk in sugar, egg, salt and cardamom.
Stir in slowly the flour until you get a dough that starts not to stick anymore neither to the walls of the bowl nor your hands.
Melt the butter, knead it in the dough, and continue kneading until you get a smooth dough.
As usual, you should "work" some air in the dough, to be light.
Let it rise for 30-45 minutes, to about double size.

Depends what you'll do the rest might differ from here onwards at every recipe.