How to Make It
Preheat the oven to 350°. Remove the turkey from the refrigerator at least 30 minutes before roasting. Pat the turkey dry and set it on a V-shaped rack in a large roasting pan. Rub the turkey all over with the oil and season it inside and out with salt and pepper. Stuff the cavity with the lemon halves, crushed garlic, thyme, rosemary, sage and bay leaf. Roast the turkey for about 2 1/2 hours, until golden all over and an instant-read thermometer inserted between the leg and thigh registers 165°.
In a small bowl, mix the apricot jam, lemon juice, lemon zest and sage and season with salt and pepper. Microwave the glaze until thinned slightly, about 20 seconds.
Brush the turkey with half of the glaze and roast for about 15 minutes, until the skin is mahogany-colored. Brush the turkey with the remaining glaze and roast for about 15 minutes longer, until the skin is deep mahogany and an instant-read thermometer inserted between the leg and thigh registers 175°. Tilt the turkey to drain all the juices from the cavity into the roasting pan. Transfer the turkey to a carving board and let rest for 45 minutes.
Skim the fat from the drippings in the roasting pan. Set the roasting pan over high heat and bring to a boil. Add the turkey stock and cook for 2 minutes, scraping up the browned bits from the bottom of the pan.
In a medium saucepan, melt the butter. Add the flour and cook over moderate heat until smooth, about 2 minutes. Strain 3 1/2 cups of the liquid in the roasting pan into the saucepan and whisk to blend. Bring the gravy to a simmer and cook over moderately low heat, whisking occasionally, until slightly thickened, about 5 minutes. Stir in the parsley, sage and thyme and season with salt and pepper. Pour the gravy into a small pitcher. Carve the turkey and serve with the gravy.