• Dry brine the turkey:
• First thing in the morning, or even the night before, place clean turkey on a baking sheet. Pour salt all over the outside and inside cavity of the turkey. Cover turkey with foil, plastic wrap, a paper bag, or paper towels. Place baking sheet with covered turkey in the fridge for 2-3 hours or overnight. Remove from fridge and let stand 30 minutes. Shake off excess salt.
• Preheat oven to 350 degrees. Place turkey breast-side-up on a rack in a roasting pan. In a small bowl, mix the butter and anchovy paste into an anchovy butter. Gently lift the skin away from the breast meat, and shove several tablespoons of anchovy butter down as far as possible underneath skin. Spread remaining butter all over outside of turkey to make sure entirely of skin is coated. Stuff turkey cavity with onion quarters and a selection of fresh herbs. Truss together legs if not already pre-tied. Tuck wings under the bird if poking out to prevent them from burning. Pour chicken broth onto bottom of roasting pan.
• Place roasting pan with turkey into oven and let cook 30 minutes. Lower heat to 325 degrees. Baste turkey with pan drippings and repeat every 20 minutes until 2.5-3 hours cook time has passed. If skin on the breast looks like it’s starting to burn, tent the breast with foil to prevent overcooking the breast meat. Cook until an internal meat thermometer reads 175 degrees when placed into the thickest part of the thigh, until pre-inserted indicator pops out, or if cutting between thigh and leg, the juices run clear.
• Remove from oven and let stand 20-30 minutes. Drain drippings from roasting pan into gravy separator. Make gravy recipe below while turkey stands. Carve turkey and serve with gravy.

To Make the Low Carb Gravy

• In a medium saucepan, heat drippings, chicken broth, butter, garlic powder, and onion powder until melted and hot but not yet boiling. Remove 1/3 cup of the hot liquid into a smaller bowl and whisk in 1 teaspoon arrowroot powder until dissolved into a slurry, then pour back into sauce pan. Repeat one to two more times with arrowroot powder slurry. Bring to boil, then turn down heat to a simmer and let sauce reduce, until gravy thickens to desired consistency, about 15-20 minutes, whisking frequently. If the gravy still feels too thin, make the arrowroot powder slurry, 1 teaspoon at a time, until desired thickness. Be careful not to over thicken the gravy, lest it become too gooey. Season with salt and pepper to taste, if needed. Remove from heat and whisk in heavy cream, if desired, for a thicker, richer gravy. Serve immediately.