Explained
Köy, böreklik or dürüm lavaş: which one do you use for what?
The three types look alike and often get used interchangeably. That usually works, but not always: a sheet that is too thin for a generous filling tears, and a sheet that is too sturdy for gözleme turns tough. Here is what to watch for.
Köy yufka: thin and supple
Köy yufka is the village version: thin, round and supple. The sheet is deliberately so thin that it cooks through quickly and stays light.
Use it where you want layers that sit against each other without becoming heavy. For börek in a dish, for gözleme on the griddle, or simply to tear off at the table during a meal.
Böreklik: a touch sturdier
Böreklik is cut to size for börek. The sheet is a fraction sturdier, and you only notice that difference once you fill it: it holds spinach, cheese or minced meat instead of letting the moisture soak straight through.
In the oven it stays light and flaky. For a börek that has to stand for half an hour before it reaches the table, this is the type that keeps its shape.
Dürüm lavaş: larger and pliable
Dürüm lavaş is larger and made for rolling. The pliability is the point: a fully loaded dürüm with meat, vegetables and sauce has to roll up tightly without tearing at the fold.
It also suits tantuni, and wraps you want to bite into firmly without the bottom giving way.
In short
If you are baking in the oven with a filling, böreklik is the safest choice. If you are rolling, dürüm lavaş. Everything in between, and certainly anything where you use the sheet flat, works with köy yufka.