Cut the tangerines and papaya into small pieces and toss in a little flour.
Beat the eggs with the sugar and vanilla sugar. Mix flour with baking powder and stir into the egg-sugar mixture with the buttermilk. Add a few drops of the butter vanilla flavoring. Fold in the fruit pieces.
Preheat the oven to 150 degrees. Grease a cake pan and pour the batter into the pan. Bake the Gugelhupf for about 50 minutes (test with a stick! ). By a cup is meant a cup with a capacity of 1/4 liter.