Za’atar, a Middle Eastern spice blend that usually contains a mix of dried thyme, sumac, and sesame seeds, is available at specialty stores or online. And while it's terrific on hummus, it's also totally optional—you can’t go wrong with a drizzle of good olive oil and a sprinkling of sesame seeds or just some flaky sea salt. Once you've got the base recipe down, here are four more ways to riff on it.