The day before, remove the giblets and any lumps of fat from the turkey cavities. Wash the turkey well and blot dry. Season the inside with salt and pepper. Loosen the turkey skin from the meat. To do so, start at the neck and tunnel your fingers, then whole hand, under the skin to separate the skin from the breast meat. Slide your hand down to loosen the skin over the thighs, drumsticks and back. Work carefully so as not to tear the skin.
Prepare the marinade. Mash the garlic and salt to a paste in a mortar with a pestle. Pound in the pepper, cumin, and oregano and last of all the lime juice or sour orange juice. If you do not have a mortar and pestle, puree the ingredients in a blender. Add 3 tablespoons marinade to the main cavity and 1 tablespoon to the neck cavity. Place the remaining marinade under the skin. Work over a roasting pan to catch any runoff from the marinade. Place the bird in a large plastic bag with any excess marinade. Marinate the turkey overnight in the refrigerator,
turning several times.
Heat the oven to 300 degrees F.
Thinly slice the butter and place half of the slices under the skin. Melt remaining butter. Truss the turkey and place it, breast side up, on a rack in a roasting pan. Brush the skin of the bird with some melted butter. Loosely drape a large piece of cheesecloth over the skin, then pour the remaining butter and marinade over the cheesecloth. Roast the bird for 2 hours. Baste with the juices and melted butter that collect in the pan. Lift the cheesecloth from time to time to keep it from sticking to the bird. Increase oven temperature to 350 degrees F and roast for 1 hour. Increase the heat to 400 degrees F and remove the cheesecloth from the turkey. Roast for 15 to 20 minutes, basting frequently.
When cooked, the skin will be golden and the leg juices will run clear when pricked with a fork. The internal temperature should be 185 degrees F on an instant-read thermometer and the drumstick should feel loose when wiggled.
Transfer the turkey to a platter or cutting board. Let stand for 15 minutes before carving.
Strain the pan juices and serve in a gravy boat on the side.