Place chicken bottoms in a pan. Arrange potatoes next to and in between the chicken pieces. Combine the sliced onion and rest of ingredients in a small bowl. Smear this mix over the chicken and potatoes. You can cover, label, and freeze at this point.
If preparing fresh, preheat oven to 350°F. Bake covered at for 2 hours and then uncover and bake for 30 minutes until browned to your liking.
If freezing: Defrost overnight in the refrigerator. In the morning, place in a 300ºF oven and bake all day, covered. About an hour before serving, raise temperature to 350°F and uncover. Bake until browned to your liking.