Turkeys can be cooked in the oven overnight, and turkey breasts are easily prepared in a slow cooker. Turkeys should be fresh or thawed before cooking them overnight.
Prepare a whole roasted turkey by cooking it overnight in the oven. To cook the turkey in this manner, a heavy duty enamel roaster with a lid is essential; aluminum roasting pans and foil do not allow the turkey to cook properly and safely. Begin by rinsing and drying the turkey, then seasoning with salt, pepper, herbs and butter if desired. Celery and onions can be placed inside the turkey cavity.
Preheat the oven to the temperature recommended on the turkey's packaging, generally 325 degrees Fahrenheit. Arrange the turkey breast side up in the roaster, and cover with the lid. Cook the turkey at half the time instructed on the label, plus 30 minutes. For example, cook a 13 pound turkey for two hours and 30 minutes, because the instructions say to cook for four hours.
Turn the oven off, and leave the turkey in the oven with the door shut at least 6 hours, or overnight. Remove, slice, and serve or refrigerate the next morning.
Cook a turkey breast in a slow cooker overnight by spraying the sides of the cooker with cooking spray. Arrange the breast inside the cooker, then brush with honey mustard and sprinkle with salt, pepper, basil, rosemary and thyme. Pour chicken broth over the turkey and cook on low overnight or for seven to eight hours.