1. Preheat oven to 450°F. Mix mustard, sage, thyme, and chives in small bowl.
2. Rinse turkey with chilly water. Pat dry with paper towels. Rigorously insert fingers beneath pores and skin, starting at neck cavity and sliding down over breast forming to type pocket between pores and skin and turkey breast. Spoon mustard combination into pocket. Use fingers to therapeutic massage outdoors of pores and skin, spreading combination into even layer. Place turkey, breast facet up, on rack in shallow roasting pan.
3. Place turkey in oven. Scale back warmth to 325°F. Roast turkey 18 minutes per pound unstuffed (20 minutes per pound stuffed) or till inner temperature reads 165°F on meat thermometer inserted into thickest a part of thigh not touching bone. As soon as turkey browns, tent with foil for the rest of roasting time. Switch turkey to carving board; reserve pan drippings. Loosely tent turkey with foil; let stand 20 minutes earlier than carving.
4. In the meantime, pour reserved drippings from roasting pan into glass measuring cup. Spoon 2 tablespoons into medium saucepan; warmth over medium warmth. Add flour; cook dinner and stir 1 minute. Add broth; simmer till thickened, stirring consistently. Spoon off fats from remaining pan drippings and discard. Add drippings to saucepan. Stir in half-and-half, salt and pepper.
5. Take away and discard turkey pores and skin. Carve turkey and switch to serving platter. Serve with gravy.