Preheat oven to 450 degrees. Rinse and clean out chicken. Cut peeled garlic into chunks. Pierce chicken skin slighly and stuff the garlic under the dkin. Do this on both legs in several places and under the skin of the chicken breast.
Sprinkle chicken with Cajun seasonings on all sides. Sear chicken on a hot grill or a grill pan. You want the chicken almost blackened, but not burnt.
Layer peeled potatoes cut into large wedges on the bottom of a large roasting pan. Add additional chopped garlic, pepper and rosemary. Place browned chicken on top of the potatoes. Add additional rosemary on top of the chicken. Cook for 1 hour and 15 minutes, uncovered.