Koulouri me Sokolata is the sweet turn on the sesame ring: a koulouri split and filled with chocolate. The plain ring is a lean savory breakfast, and this version keeps that same toasted sesame structure but pushes it toward something closer to a pastry. The interest lies in the tension, a bread that is salty, nutty, and not sweet at all, carrying a sweet filling, and whether the two read as a deliberate contrast or just a clash.
The build is the split-ring method applied to a sweet filling. A fresh koulouri is cut around its circumference and opened like a thin bagel, and chocolate goes into the gap, usually a soft chocolate or hazelnut-chocolate spread that can be smeared into the crumb, sometimes a melting piece. The ring has to be fresh and have enough soft crumb to take the spread, because a dry day-old ring just smears chocolate on a hard shell. Good execution means a clean even split, chocolate carried all the way around the loop so no bite is bare, and a restrained amount, enough to sweeten and contrast the sesame rather than bury it. Sloppy work is a stale ring that crumbles when opened, chocolate pooled at one spot so half the ring is plain bread, or so heavy a load of sweet spread that the sesame and the bready chew disappear entirely and you are essentially eating chocolate on stale toast. The whole point is the savory-sweet contrast: roasted sesame crust and lean wheat crumb against a sweet filling, and that only works if the ring is good and the chocolate is measured.
Variation is mostly about the filling. A thin chocolate-hazelnut spread melts into the warm crumb and reads almost like a breakfast pastry; a firmer chocolate gives a more defined sweet bite against the bread. Some versions warm the filled ring so the chocolate loosens into the crumb, others serve it at room temperature off a cart. This is the dessert end of the koulouri range, and the savory filled forms, with cheese and with ham and cheese, each deserve their own article rather than being crowded in here. The plain sesame ring it is built on, the Koulouri Thessalonikis, is covered separately.