Warm milk to 110F.

Sprinkle yeast over warm milk and stir until dissolved.

Let sit until foamy (5 minutes).

Combine flour, sugar, salt, cardamom, and 4 tablespoons of butter in a mixer bowl.

Beat on low speed until butter is incorporated (3-4 minutes).

Pour in yeast-milk mixture and mix until dough comes together.

Add eggs and yolk and mix until just combined (2-3 minutes).

Do not overmix.

Turn dough onto a lightly floured surface, including loose bits.

Gently knead into a smooth ball (30 seconds).

Wrap well with plastic and refrigerate for at least 2 hours or overnight.

Roll out dough to an 18x10 inch rectangle (1/4 inch thick).

Remove excess flour with a pastry brush.

Distribute remaining butter over two-thirds of the dough.

Fold the unbuttered third over, then fold the remaining third.

Roll out dough again to an 18x10 inch rectangle.

Fold dough into thirds and refrigerate for 1 hour.

Repeat rolling and folding two more times, refrigerating for at least 1 hour between turns.

Mark the dough after each turn to keep track.

Refrigerate dough tightly wrapped for at least 4 hours or overnight.

Freeze for up to 2 weeks (thaw in refrigerator overnight before using).