It's baked in a fluted ring pan called a 'Reindl' — the pan gave the cake its name, not the other way around.
A rich, buttery yeast dough is rolled with a swirl of cinnamon, sugar, walnuts, and raisins, coiled into a ring pan, and baked until deeply golden. Carinthian bakeries and market stalls sell it sliced, especially heavy around Easter and local festivals.