Za'atar is a very popular Middle Eastern spice blend, in restaurants served as a tabletop condiment or as a dip mixed with olive oil. There are plenty of variations, all based on sesame seeds, sumac, and thyme or a similar herb. The combination of nutty, sour, and savory makes the taste so versatile and irresistible. Try it with roasted chicken, vegetables, on pizza, hummus, or as a dip.