Combine salt & pepper in a small bowl. Pat the roast dry with paper towels and rub with the salt/pepper mixture. Wrap kitchen twine twice around the widest part of the roast and tie it tightly. Refrigerate the roast, uncovered, at least 6 hours and up to 24 hours.
Set oven rack to lower-middle position and heat oven to 475°F. Line a baking sheet with foil and spray a metal baking rack with nonstick spray, and set the rack over the baking sheet.
Set roast, bone-side down and brush with 4 tablespoons butter.
Roast the meat until the internal temperature registers 110°F, about 1 hour.
Reduce oven temperature and remove roast from oven. Use two bunches of paper towels flip the roast over to bone side up.
Brush the roast, inside and out, with the glaze.
Roast the roast, basting every 15 minutes, until the internal temperature registers 140°F, 1-2 hours.
Transfer the roast to a carving board, brush with the glaze and tent loosely with foil to let rest 20-30 minutes.
In a small saucepan, bring the glaze to a low boil over medium-high heat. Reduce the heat to low, cover the glaze and simmer about keep warm until ready to serve.
Remove the twine from the roast and carve the meat between the bones.
Serve the sauce with the roast, and…