Although they don't look it, turnips are actually in the cabbage family. This is evidenced in their mild cabbage-like flavor, which can be a bit spicy when eaten raw but turns softly sweet when cooked. The interior is actually solid and crisp, similar to a potato.
Look for the smaller turnips that feel very firm. These will be sweeter and more tender than the larger ones, which can tend to get woody. And don't throw away the greens! These have a great spicy flavor and can be quickly sautéed or steamed.
In cooking terms, you can treat a turnip much like any other root vegetable. Peel off the skin and cut it into bite-sized chunks. Turnips can then go into a braise or a stew, or they can be roasted until crisp on the outside and soft in the middle. Very small and sweet turnips can even be shaved raw into salads like radishes.
What are your favorite ways to eat turnips?
Related: Tip: Add Rutabaga to Mashed Potatoes