Mix sifted flour, salt, baking powder and vanilla sugar in a separate container in advance.
Beat butter with powdered sugar in a blender. Add sour cream. Add the dry mixture to the butter and knead well. Wrap the dough in cling film and place in the refrigerator for 20 minutes.
Prepare the filling: rinse the raisins, then scald with boiling water for a few minutes and pass through a meat grinder. Divide the dough into three parts. Roll each into a thin circle and divide into 8 parts. Place the filling on the wide part and roll into bagels. Bake in an oven preheated to 200-210 degrees, 15-20 minutes until golden brown.
Dust the bagels with powdered sugar and serve with a cup of hot, strong tea.