Roll out the puff pastry and spread a large tablespoon of crème fraîche with herbs on top. Leave about 2 cm free on one short side. Cut the feta and olives into small cubes and spread on the dough. Season the topping with pepper and herbs. I would leave out salt because the brine of feta and olives is usually well salted, but that`s a matter of taste.
Roll up the puff pastry from the narrow, coated side. Cut the roll into 1 - 2 cm wide slices and spread them on a baking sheet. I always use parchment paper. Bake the puff pastry rolls in the oven for 12-15 minutes at 200 degrees, but keep an eye on them so that they don`t burn.