Heat half of the water in a large pot. Add in the salt and sugar and stir until dissolved. Pour the water into a large, clean bucket and stir in the remaining water, garlic and pickling spices. Submerge the turkey breast in the brine and refrigerate overnight.( If you don’t have room in your fridge, add a 10lb bag of ice to the brine and pour into a clean cooler, then add turkey to it.)
Preheat the oven to 450 degrees. Rinse the turkey and place on a rack in a roasting pan. Pat dry with paper towels. In a small bowl, mix together the butter, sage, rosemary and garlic. Slide a couple of fingers underneath the skin of the turkey breasts to loosen, then spread the butter mixture underneath the skin as best you can. Smear any remaining butter on top of the skin and then sprinkle with salt and pepper. Stuff the cavity of the turkey with the oranges, bay leaves and onion. Use a small piece of aluminum foil tucked under the bottom to keep them from falling out.
Roast the bird for 20 minutes at 450 degrees, then turn the oven down to 375 degrees and cook until the internal temperature reaches 165 degrees. Remove from the oven and let it rest. Meanwhile, make the gravy from the pan drippings.
Heat the roasting pan over medium heat on the stove top. Scrape the brown bits off the bottom with a whisk. Add an equal amount of flour to the fat in the pan. Cook for 1 minute then slowly add in chicken broth, whisking constantly, until the desired thickness is achieved. Season with salt and pepper. Strain if desired.
Make a cut down the backbone and a cut across the ribs of the turkey in order to remove the breast from each side of the carcass whole. Slice the breast into serving pieces and serve with gravy.