The roots (Rhizomes) of the Curcuma longa plant are boiled for several hours then dried and ground into a powder.
Turmeric powder is mainly used in Middle Eastern meat and seafood dishes.
Here are some example recipes using Turmeric powder:
Kuwaiti Chicken Daqoows
Garlic Tomato Sauce Chicken on rice
Jordanian spicy yogurt lamb on rice dish
Turkish shrimp stew
Prawns cooked in a tomatoes, pepper, chilli and garlic stew