To cook cornish hens you roast them like chicken. You can leave them whole or cut them in two halves. Wash the hens and pat dry with paper towels. Sprinkle lightly with salt and pepper place in a baking dish breast side up. Bake in preheated oven at 350 until done or internal temperature reaches 165 degrees F when a meat thermometer is inserted in the thickest part of the bird. If desired you can brush a little melted apple jelly or orange marmalade over the hens during the last five minutes of baking for an easy glaze.