- Heat oven to 4500F. Place onions in large shallow roasting pan. Slip fingers under skin of chicken over breast meat to make a pocket. Spread 2 tablespoons of the butter under skin in pocket; arrange rosemary springs over butter under skin in pocket.
- Tuck wings behind back; place chicken breast-side up, over onions. Spread remaining 2 tablespoons butter over outside of chicken; sprinkle with 1 teaspoons of the chopped rosemary, pressing lightly to adhere.
- Bake 20 minutes. Turn chicken breast-side down. Arrange potatoes around chicken; sprinkle potatoes with remaining 1 tablespoon chopped rosemary, 1/2 teaspoon salt and 1/4 pepper.
- Bake an additional 20 minutes. Turn chicken breast-side up; stir potatoes and onions. Bake an additional 20 minutes or until internal temperature of thickest part of thigh reaches 1700F to 1750F. Let stand in warm place 10 minutes before carving. Serve with potatoes and onions.
2 large onions, cut into 1-inch wedges
1 (4 1/2 lb) chicken, patted dry
4 tablespoons unsalted butter, softened, divided
4 (4 inch) springs fresh rosemary
1 1/2 teaspoons kosher salt, divided
3/4 teaspoon pepper, divided
3 tablespoons chopped fresh rosemary, divided
1 1/2 lb. assorted fingerling potatoes , unpeeled, halved or quartered if large