Remove and discard giblets and neck from chicken. Rinse chicken with cold water; pat dry. Trim excess fat. Starting at neck cavity, loosen skin from breast and drumsticks by inserting fingers, gently pushing between skin and meat.
Combine the rosemary and the next 4 ingredients (rosemary through garlic). Rub mixture under loosened skin, and rub over breast and drumsticks. Lift wing tips up and over back; tuck under chicken.
Place the chicken, breast side up, on a broiler pan coated with cooking spray. Pierce the skin several times with a meat fork. Insert a meat thermometer into the meaty part of thigh, making sure not to touch bone; brush chicken with Lemon Curd. Arrange lemons around chicken. Bake at 450° for 30 minutes. Reduce the oven temperature to 350° (do not remove chicken from oven), and bake for an additional 1 hour or until thermometer registers 180°. (Cover the chicken loosely with foil if it gets too brown.) Remove the chicken from the oven. Cover the chicken loosely with foil, and let stand for 10 minutes. Discard skin. Serve with lemon halves, and garnish with rosemary, if desired.