Traditional štruklji are made with filo pastry and have a filling of your choice. Mostly, you can get cottage cheese ones or the very popular buckwheat ones with a walnut filling. The interesting thing about štuklji is they can be served salty as a side dish next to meat (especially tasty when served with venison) or as a dessert with breadcrumbs for the topping. Apart from the most famous ones, there are some other flavours gaining popularity: boiled apple, baked apple, and tarragon. Tarragon is widely used as a seasoning in Slovenia, so I suggest you give them a try.