Remove and discard giblets and neck from chicken. Rinse 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 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 the thigh, making sure not to touch bone. Brush chicken with Lemon Curd; arrange lemons around chicken. Bake for 30 minutes. Reduce heat to 350 degrees (do not remove chicken from oven), and bake an additional 1 hour or until thermometer registers 180 degrees. (Cover the chicken loosely with foil if it gets too brown.) Remove from the oven. Cover the chicken loosely with foil, and let stand 10 minutes. Discard skin. Serve with lemon halves, and garnish with rosemary sprigs, if desired.