Thaw the puff pastry, but not completely, and spread it out. On it, evenly distribute the filling made from the yogurt, crumbled feta cheese, one egg, the egg white from the other. Then sprinkle on the spices.
Roll up the puff pastry (not too tight), so the filling doesn't pour out. Cut it into slices approximately 1/2″ (1 cm) thick.
Arrange the puff pastry pies in a dry, non-buttered tray, smear them with the separated yolk.
Bake in a very hot oven at 410°F (210 °C) until browned.