Gather all ingredients.
Prepare brine: in a large container or pot, whisk together tea, 3 tablespoons salt, Creole seasoning, lemon zest, and juice until salt dissolves.
Add chicken, making sure it is fully submerged in the brine. Refrigerate 6-10 hours.
Preheat oven to 425°F. Thirty (30) minutes before you are ready to cook, remove chicken from brine and pat dry. Rub chicken with mayonnaise and sprinkle with ½ teaspoon salt and ½ teaspoon pepper. Tie together legs and tuck wing tips under chicken.
In a large oven-safe skillet, braiser pan, or roasting pan, toss potatoes, carrots, and sweet onion wedges together with olive oil, remaining ½ teaspoon salt and pepper, and rosemary. Place chicken on top of vegetables.
Transfer pan to preheated oven; roast until a thermometer inserted into thickest portion of breast registers 165°F, 1 hour to 1 hour, 10 minutes. Remove from oven and let stand 10 minutes before serving.
