The blue potato (or purple potato)

The blue potato (or purple potato) originated in South America.
It has purple skin and flesh, which becomes blue once cooked. 
Purple potatoes have deep violet, ink-colored skin and flesh.
Purple potatoes are an invaluable staple in a South American kitchen and used in many recipes.
Purple potatoes can be roasted, braised, boiled, baked, fried for chips, and they pair well with savory herbs, garlic, pork, poultry, artichokes, both rich and mild cheese, other starchy vegetables such as corn and shelled beans and of course, salad greens.