Mix the quark, sugar, egg yolk, oil and milk together. Mix the flour and baking powder, add to the quark and knead into a smooth dough. Mix very soft butter, honey and vanilla sugar to a cream. Roll out dough. Brush the buttercream onto the dough, avoiding the edges. Roll up the dough and cut into approx. 1 - 2 cm thick slices and place on a baking sheet lined with baking paper.
Preheat the oven to 180 convection.
Bake the snails for 15 minutes. Roll the hot snails in a mixture of powdered sugar and vanilla sugar.
Note: The buttercream is absorbed into the dough, so it is not a filling!