To Roast Turkey:
Put oven rack in lowest position and preheat oven to 450°F. Rinse turkey inside and out, then pat dry. Brush turkey with melted butter and sprinkle turkey cavities and skin with salt and pepper. Combine fresh herbs and rub on skin. Stuff cavity with carrots and onion. Fold neck skin under body and secure with metal skewers, then tie drumsticks together with kitchen string and tuck wings under body.
Put turkey on rack in roasting pan. Add 1 cup low-sodium organic chicken broth to pan and roast, baste frequently with remaining broth and rotate pan halfway through roasting, until thermometer inserted into fleshy part of thighs (test both thighs; do not touch bones) registers 170°F, 2 1/4 to 2 3/4 hours.
Carefully tilt turkey so any juices from inside large cavity run into roasting pan, then transfer turkey to a platter, reserving juices in roasting pan. Let turkey stand, uncovered, 30 minutes (temperature of thigh meat will rise to 180°F).
Make Gravy While the Turkey Rests:
Mix flour and Merlot in small bowl until smooth paste forms. Set aside. Melt butter in heavy large saucepan over medium-high heat. Add mushrooms and sauté until mushrooms begin to soften, about 3 minutes. (Can be made 3 hours ahead. Cover flour paste tightly. Let paste and mushrooms stand at room temperature.)
Discard turkey neck and giblets from pan juices in roasting pan. Transfer pan juices to large glass measuring cup. Skim off fat. Add enough chicken broth to measure 6 cups and pour into large saucepan with sautéed mushrooms. Add flour paste and whisk until smooth. Bring mixture to boil, stirring frequently. Boil until thickened to light gravy, about 10 minutes. Mix in cream, thyme and sage. Season with salt and pepper. Serve turkey with gravy.
Serve turkey with gravy, various side dishes, and 2019 Domaine Carneros Estate Pinot Noir.