After reading the postings, I have a couple of suggestions: Use ghee (samna) in place of the olive oil. This, plus the onions and salt and pepper are all you need to season this dish authentically. Don't get zaatar anywhere near this dish!
And, since the Arabic word "siliq" (which Americans have corrupted to "sleek") refers to Swiss Chard, you might want to use chard instead of kale.
I love this stuff. And once you try it with samna, you won't go back to the healthy oils. It's not worth the flavor loss.