Sumac powder comes from sun-dried berries of a wild shrub that grows in subtropical and temperate climates like Southern Italy, North America and Africa. The clusters of small red berries (called drupes) that grow on the plant are sought after for their sour taste. After the berries are dried and ground, they become a deep purple powder. Sumac powder has a lemony flavor and is great for seasoning meats, stews and sauces.
Sumac is primarily used in Middle Eastern cuisine. In Arab dishes, sumac is used to garnish hummus and salads. In Turkish cuisine, sumac is an ingredient in za'atar, a popular spice blend. In Iranian cuisine, sumac is added to rice dishes and kebab.
Sumac can be used in cooking in a similar way to lemon, to add a bit of freshness and acidity. The best way to get familiar with sumac is to toast it lightly in a little bit of oil in a pan over medium heat. Stir constantly until aromatic, about 1 minute. Pull it off the heat, let it cool and pour over hummus, a salad or roasted vegetables.