Step 1

For the dry-rubbed grilled chicken: Remove the backbone from the chicken. Cut the chicken through the breastbone into two halves. Stir together the House Seasoning, brown sugar, oregano, paprika, parsley and a couple of pinches of salt in a bowl. Rub under the skin and all over the chicken halves.

Step 2

Prepare a grill for direct and indirect cooking: Heat one side of the grill to medium heat. Leave the other side unlit.

Step 3

Place the chicken skin-up on the grates on the unlit side of the grill. Grill, with the lid closed, until the skin begins to brown, about 45 minutes. Transfer the chicken to the lit side of the grill, starting skin-up, and cook until the chicken is done and a meat thermometer registers 165 degrees F when inserted in the thickest portion of the thigh (avoiding bone), 12 to 15 minutes on each side.

Step 4

For the Alabama white sauce: Stir together the mayonnaise, brown sugar, vinegar, Dijon mustard, horseradish, hot sauce, dry mustard, lemon juice, and salt and pepper to taste in a medium bowl.

Step 5

Transfer the chicken to a serving platter. Pour the sauce over the chicken and serve immediately.

Step 6

Stir together the garlic powder, onion powder, paprika, salt and pepper in a small bowl. Store in an airtight container at room temperature.