Cut the vanilla pod in half lengthwise and scrape out the pulp. Boil milk in a pot with vanilla pod and pulp, salt, 25 g sugar and 1 tablespoon fat. Remove the vanilla pod. Stir in polenta slowly and bring to the boil.
Allow to swell for 5-10 minutes over a low heat while stirring continuously. Sort the blueberries and carefully fold them into the polenta. Grease baking tray. Spread the hot polenta mixture about 1 cm thick to form a square (about 20 x 20 cm) on the baking tray.
Place in a cool place for about 2 hours.
Mix cinnamon and 30 g sugar. Cut polenta into squares (approx. 5 x 5 cm). Roll polenta pieces in the cinnamon-sugar mixture. Heat the fat in portions in a large pan. Fry the polenta pieces in portions on both sides for 1-2 minutes in the fat until golden brown.
Mix crème fraîche with liqueur. Arrange slices on plates and add crème fraiche.