Maple-Brined Turkey Roulade with Creole Mustard and Herbs

For brining:
12 pound bone-in turkey breast or 2 (3 pound) boneless breasts, thawed, if frozen (as a rule of thumb, allow about a pound of raw, bone-in turkey per person, or 1/2 pound per person if boneless)
1 gallon water
1 cup course kosher salt
1/2 cup packed brown sugar
1 cup maple syrup
1/2 bunch fresh thyme
1/2 bunch fresh sage
1 gallon ice cubes or crushed ice
For roulade:
Kosher salt and freshly ground black pepper to taste
4 tablespoons creole or stone-ground mustard
1 tablespoon each chopped fresh rosemary, sage and thyme
1/2 cup chopped fresh parsley

To brine turkey:
Line a cooler with 2 kitchen garbage bags, one inside the other. Rinse turkey breast. Place turkey in plastic bag. Combine water, salt, sugar and maple syrup in large bowl or pot. Bruise the herbs by rubbing them vigorously between your hands to add to the brine. Stir until salt and sugar dissolve. Mix in ice cubes. Pour brine over turkey in plastic bags. Gather tops of bags together, eliminating air space above the brine; seal with a twist-tie. Cover with additional ice and let sit, adding more ice if necessary to keep turkey below 40 degrees.
To make roulade:
Remove turkey from brine, rinse thoroughly under cold water and pat dry. Use a very sharp boning knife or other knife with a thin, flexible blade to skin, debone and butterfly the breast. First, remove skin, keeping it in one piece if possible. You can probably pull most of the skin off with your hands; make very shallow strokes with the knife if you need help separating the skin from the breast. Cut skin in half lengthwise and reserve. Cut away any major pockets of fat or white areas remaining on the turkey breast. Debone the turkey by starting at the neck cavity and cutting along the top edge of the breastbone and down the edge of the wishbone and keelbone, peeling the breast away from the skin as you cut and leaving as little meat on the bones as possible. Make shallow, short cuts so you can correct your stroke if you see that you are leaving too much meat on the bones; follow the seam of the muscles. Remove the half-breast and repeat for the other side. The bones can be frozen to use in making stock or soup. To butterfly each half-breast, lay it, outer surface down, lengthwise on the cutting board, with thinner, pointed end nearest you. Starting at the thicker top part, score the breast half down the middle lengthwise, being sure not to cut all the way through to work surface, stopping about 1 inch from the end closest to you. Visualize the turkey as a book jacket with the central lengthwise cut as its spine; you want to cut 2 flaps on each side that you can fold open outward. Turning knife blade parallel to the board and beginning at the center lengthwise cut, slice parallel to the board and toward the outer edge of the breast; do this on both sides to form 2 flaps, so taht you can open the flaps outward. Open flaps and cover butterflied breast with plastic wrap. Pound turkey with a heavy skillet, the flat side of a meat mallet or a rolling pin until it is 1/2 inch thick. Repeat with remaining breast half.
Preheat oven to 350 degrees (if you will be baking the turkey in the same oven with the dressing, increase the temperature to 375).
Place the two butterflied breast halves on a cutting board, outer side down. Sprinkle liberally with salt and pepper and spread with the mustard. Mix the chopped herbs together and sprinkle over the breasts. Roll each breast half like a jellyroll and cover it with half of the reserved skin. Tie rolls firmly in several places with butcher's twine. Place the two rolls on a rack in a roasting pan, skin side up. Roast until they are dark golden brown outside and a meat thermometer reads 165 degrees at the fattest part of the breast, 1 1/2 to 2 hours. Remove from the oven and allow to reast at least 15 minutes before carving.