- Mix first five ingredients in small bowl.
- Pat turkey dry with paper towels and place on rack set in large roasting pan. Place herb sprigs and lemon in main cavity. Brush turkey with oil. Rub herb mix all over turkey.
- Preheat oven to 425 degrees. Drizzle melted butter all over turkey. Pour two cups broth into pan. Roast turkey 45 minutes.
- Remove turkey from oven and cover breast with foil. Reduce oven temperature to 350 degrees. Return turkey to oven and roast for one hour while basting with juices from bottom of the pan.
- Remove foil from turkey and pour remaining one cup of broth into pan. Continue roasting turkey until meat thermometer inserted into thickest part of thigh registers 180 degrees or until juices run clear when thickest part of thigh is pierced with skewer, basting with pan juices, about 1 hour 40 minutes longer.
- Transfer turkey to platter; tent with foil. Let stand 30 minutes. Reserve liquid in pan for gravy.
- Melt butter in saucepan over low heat. Add flour to make roux and cook until light brown color. Add sherry and stir to dissolve roux.
- Add rosemary and reserved pan juices or broth. Stir to mix thoroughly and bring to a simmer. Reduce heat to low. Continue to stir the gravy.
- Before serving, add cream and thyme. Salt and pepper to taste.