Danish pastry dough
Mix the flour, salt and sugar in a bowl. Add the butter and rub together using your hands to form an even, crumbly mixture, then create a well in the middle. Pour the milk, yeast and egg into the well, mix and combine quickly to form a smooth dough. Cover the dough and leave to rise at room temperature for approx. 1½ hrs.
Fold the dough
On a lightly floured surface, roll out the dough into a rectangle approx. 1 cm thick. Cover one half of the rectangle evenly with butter, leaving a border of approx. 1 cm. Fold the other half over the top, press the edges down firmly, cover and chill for approx. 30 mins. Roll out the dough into a rectangle approx. 1 cm thick. Fold the short sides into the middle, then fold one half over the other to create 4 layers. Cover the dough and chill for approx. 1 hr., roll out again, fold to make 4 layers, cover and chill for approx. 1 hr.
Mix the butter with all the other ingredients up to and including the ground cardamom.
On a lightly floured surface, roll out the dough into a rectangle (approx. 30 x 50 cm). Spread the filling on top. Cut the dough lengthwise into thirds. Roll up one piece of dough, extend the roll with the other pieces of dough. Place the swirl in the prepared tin, cover and leave to rise for approx. 30 mins.
Approx. 50 mins. in the lower half of an oven preheated to 180°C. Remove, allow to cool slightly on a rack while still in the tin, remove the tin frame, leave the cardamom swirl to cool on the rack.