Mix the flour, salt, sugar, cinnamon and yeast in a bowl. Add the butter, milk and egg, knead to form a soft, smooth dough. Cover and leave to rise at room temperature for approx. 2 hrs. until doubled in size.
Mix the butter, sugar, cinnamon, ground cardamom and nuts. On a lightly floured surface, roll out the dough into a rectangle (approx. 40 x 50 cm). Spread the filling on top, leaving a border of approx. 1 cm all the way around. Roll up the dough from the long edge. Without exerting pressure, cut into approx. 3 cm slices using a bread knife, place on a baking tray lined with baking paper, allow to rise at room temperature for approx. 30 mins.
Approx. 15 mins. in the lower half of an oven preheated to 220°C. Remove, allow to cool slightly.
Mix the icing sugar and lemon juice, spread the icing over the cinnamon rolls and leave to cool on a rack.