Dissolve the yeast, and add the eggs one by one, cardamom, salt, sugar and room temperature butter or margarine into hand temperature water/milk. Add the flour little by little and knead the dough completely until it is so tough that it completely separates from your hands and the sides of the bowl. Cover the dough with a lid or a cloth and leave to rise for about half an hour in warm windless place.Divide the dough into three parts. Reserve about 250 g of softened butter for each part. Roll the dough on the well-floured surface into a rectangular (about 30 x 50 cm) sheet.
Spread butter on half of the sheet. Fold the non-buttered side over the buttered side. Roll it again into a rectangle the same size as before and again spread butter over half of it and fold. Add flour to the baking surface between every rolling. Each dough shell should be rolled and folded over three times altogether. Cut the dough vertically into 1½-2 cm wide dough strings. Twist the strings into a spiral and shape into a knotty ball. Spread one generous tablespoonful of oven-stable marmalade over each bun. Make the glaze by whipping the eggs lightly and adding sugar, salt and water. Glaze the buns.Let the buns rise on a baking sheet for 15-20 minutes. Bake for 12-15 minutes in a preheated oven (240°C). Sift the icing sugar over the cooled buns.