In Bulgaria, fries may be topped with sirene, a grated white brine cheese.
Sirene is a traditional Bulgarian cheese made from goat, sheep, cow, buffalo milk, or blends of those milks. It is usually slightly crumbly, mildly grainy, salty, and sold in blocks. Grating it over hot fries gives the potatoes a savory topping that softens slightly from the heat.
Sirene is much more than a fries topping in Bulgarian cooking. It appears in shopska salad, banitsa, stuffed peppers, omelets, pastries, and other everyday dishes. Bulgarian white brine cheese is sometimes compared with feta, but feta is a distinct Greek cheese with its own protected designation and production rules; the names should not be treated as exact synonyms.
The name also helps distinguish this cheese from kashkaval, another important Bulgarian cheese. Kashkaval is a firmer yellow cheese, while sirene is the soft white brined variety. In 2023, Bulgarian white brine sirene received European Union protected designation of origin status.