Purple yams are prevalent in many Asian cultures, and they are regularly turned into pastes or cooked and eaten whole for their sweet, delicate flavor. Purple yams are becoming widely available in the United States, and they can be cooked in much the same way as the more traditional yam or sweet potato. Purple yams pair particularly well with light roasted meats, and they can be used in cold salads or peeled and mashed for a unique side dish.
Place a shallow pan on the bottom rack of the oven or line the rack with aluminum foil to catch any drippings from the two yams. Preheat the oven to 375 degrees Fahrenheit.
Wash the yams under cold, running water, scrubbing any particularly dirty parts with a vegetable brush. Allow the yams to drain in a colander for 5 minutes before patting them dry with clean paper towels.
Place the yams on a baking sheet or plate and brush them with extra virgin olive oil or a 50:50 combination of extra virgin olive oil and melted, unsalted butter. Lightly sprinkle the yams with sea salt or kosher salt and freshly ground black pepper to taste, turning them once to season both sides.
Put the yams on the center rack in the oven and cook them for 45 minutes. After 45 minutes, poke the yams in the center with a fork. If the yams are fully cooked, the skin and inside should be easily penetrated by the tines of the fork.
Continue cooking the yams in 10-minute intervals if they are not fully cooked, checking the yams every 10 minutes.
Remove the yams from the oven and allow them to cool for 5 minutes before slicing and serving them. For cold salads and dishes, allow the yams to cool at room temperature for 1 hour.