Bake in the preheated oven to 200 degrees C for 15 minutes, then bake for another 5-10 minutes to 180 degrees C. Time may vary a bit, depending on each oven, so just make the necessary adjustments.
If you bake the rolls in the oven which has not been preheated to 200 degrees C, the butter will drain from the pastry and the rolls will get very oily and will collapse.