In small bowl, combine thawed orange juice concentrate (do not use regular orange juice!), marjoram, nutmeg, and garlic powder. Place onions in bottom of 3-4 quart slow cooker. Dip each chicken breast into the orange mixture to coat and place in crock-pot over onions. Pour any remaining orange juice concentrate mixture over the chicken. Cover and cook on low for 6-7 hours until chicken is almost cooked. Add apples and cook one hour longer on low until apples are tender and chicken is thoroughly cooked.
When chicken is done, remove chicken, apples and onions to serving platter. Pour the sauce that remains in the crock-pot into a medium saucepan. Mix together water and cornstarch in a small bowl and stir into the juices in saucepan. Cook over medium heat, stirring constantly with wire whisk, until sauce is thick and bubbly. Serve the sauce over the chicken. Great with rice and steamed veggies or a salad.
