Prepare a yeast dough. Mix the flour in a big bowl with the yeast. If you use fresh yeast, stir it with lukewarm milk. Add milk, eggs, egg yolks, sugar, icing sugar and the lemon zest. Let the dough rise on a warm place for about 30 minutes until it has grown to double its size. Preheat the oven to 175 degrees. Knead the dough shortly and roll it out on a floured working surface to a rectangular shape. Put all the ingredients for the filling into a pot and let them boil down shortly. Spread the filling evenly onto the rolled-out dough. Roll the dough in, then shape the dough into a wreath. Put the wreath into a bundt cake tin that is greased and strewn with sugar. Let it rise again shortly. Bake the Carinthian bundt cake in the preheated oven at 175 degrees for 45 minutes.