I’ve been to Greece enough times to know that a Greek salad never contains lettuce. Or almost never. Doug and I ate a lot of Greek salads on our recent vacation and only one—a deviant—had leafy greens. As familiar as I am with this iconic summer dish, I did learn a few more do’s and don’ts on this trip. In fact, when I asked one of my hosts about an ingredient that most Americans include, her eyebrows shot up in alarm. She all but shuddered. So, in the service of authenticity and international relations, here are a few observations about how to make an unimpeachable horiatiki that won’t dismay any Greeks.

First, as mentioned, no lettuce. Accepted vegetables include tomatoes, cucumbers, sweet red onion and bell peppers. The tomatoes should be in big chunks, the cucumbers peeled.

Choose Kalamata olives with pits. I never once encountered a pitted olive.

If you’re using feta, don’t crumble it; instead, lay a thick slab on top. The other permitted cheese—hard to find in the U.S—is soft, fresh mizithra. Made from a blend of sheep and goat milk, fresh mizithra is consumed quickly, within a day or two, while it’s still moist and fluffy. For Greek salad, it is dolloped on top, then stirred in by the diner. A fresh sheep ricotta or super-fresh chèvre is about as close as we can get, although it’s not difficult to approximate mizithra at home.

Finely crumbled dried Greek oregano goes on top of the cheese. Forget fresh dill, mint, basil or any other herb.

Dress the vegetables with extra virgin olive oil and salt. Nothing else. Wine vinegar is not welcome, and I never tasted garlic. I add vinegar, as do many Americans, but that’s the ingredient that made my host freak out. In theory, the juices from the tomato provide the acidity.

On Crete especially, you will see small, nubby barley rusks or carob rusks (dakos) in Greek salad. They function like croutons, soaking up the juices. Crete’s most beloved appetizer, also called dakos, calls for topping barley rusks with mizithra, chopped or grated tomato, olives and lots of olive oil. (Here’s a tutorial.)

The prized part of a Greek salad is the mingled juices at the bottom. Don’t leave them behind. Grab a chunk of bread and sponge up every drop.

Lastly, if you’re traveling in Greece, don’t presume that Greek salad is for tourists. Everyone orders it. Over the three weeks we spent in Crete, Naxos and Sifnos, I noticed a Greek salad on the tables of Greek-speaking diners more often than not. It’s crunchy, refreshing and wholesome, the perfect complement to grilled fish.

Now that you know what’s permitted in Greece, go your own way. I guarantee you I’m adding wine vinegar.