Mix water and yeast and put aside for a while
Mix flour, salt and baking powder, add butter and buttermilk, mix…. add yeast mixture and make a nice dough.
Make small balls out of the dough (don't forget to do the "schleifen"). Put on a baking try (either with baking paper or a bit of oil), cut surface if you want too, let rize for at least 15 min (say until volume doubled).
Preheat oven to 220 ℃ (ca. 400 ℉). Add some water into the oven (either spray sides or put a dish with water in or both) and bake for 20 minutes.