Related to ginger, turmeric is a bright orange or yellow powder used most commonly in Indian or Asian cuisine. Medieval Europeans sometimes substituted turmeric for saffron, which was much more expensive.
Turmeric has a very subtle taste. It is earthy in quality and usually goes unnoticed or exists only as a background note in the dish. Many Indian dishes call for the use of turmeric, providing curries with their vibrant color.
Turmeric is rarely added raw at the end of a dish. Instead it is usually cooked in some fashion to help develop its flavor.
In traditional Indian cooking, turmeric is added to some dishes at the beginning. Many recipes begin by heating ghee or light oil until it is hot, adding black mustard seeds and frying them for a few seconds until they turn grey, then adding several spices to fry in the oil before adding to the main dish.
A simple recipe for this would be to prepare the mustard seeds as above (fry them in the oil, about 2 tablespoons until the popping dies down and they are turning grey), added ground coriander, cumin, red pepper and turmeric. Fry this in the oil for just a few seconds and then throw some finely diced ginger into the pan and cook for another minute.
To the above, you can then add diced onions and potatoes. The turmeric will color the vegetables as they cook and provide a beautiful shade of yellow or orange. Add some water after about 10 minutes and let it simmer for another 15 minutes. It is a great dish to have over rice and it really brings out the flavor of the turmeric.
For soups, the turmeric need not be added at the beginning if the pot will be cooking for a long time. There are soups and stews where the turmeric is added close to the end, perhaps 45 minutes to half an hour before the dish is done. This is to prevent the spice from over-cooking and preserve the unique earthy flavor.
Yogurt dishes, such as something simple like yogurt braised chicken, are a sight to behold when you add a little turmeric to the recipe.
It should be noted that while always cooked, turmeric does burn easily. When cooking, maintain a consistent flame and keep an eye on if the spices are cooking by themselves.
Enjoy turmeric. Add it to pasta, experiment with it. It is a unique and rich spice that adds a subtle flavor note to dishes it is used in.