Beat the butter until foamy and mix with the sugar, egg yolk, flour, salt, milk and crumbled yeast to form a soft dough until it comes off the mixing spoon. Prepare the yeast dough with a dough hook.
Beat the egg whites until stiff and fold in the raisins, add to the batter. Then pour the dough into a buttered and floured bundt cake pan and place in a moderately warm place to rise until the volume has doubled.
Bake for 60 minutes at approx. 170 ° C, turn out onto a sieve, allow to cool and sprinkle with powdered sugar.